Novel cancer antigen eef2

ABSTRACT

The present invention provides a method for detecting cancer using a protein expressed in various cancers, and a pharmaceutical composition for the treatment or prevention of such cancer using the protein as an indicator. Furthermore, the present invention provides a pharmaceutical composition containing a cancer antigen peptide derived from the protein. More particularly, the method comprises the step of determining the presence or amount of an eEF2 polypeptide or an eEF2 antibody in a sample obtained from a subject.

This application is a division of U.S. application Ser. No. 13/143,492, filing date of Sep. 29, 2011, which is the National Stage of PCT/JP2010/050174, filed Jan. 8, 2010, and claims priority to JP 2009-002608 filed Jan. 8, 2009, all of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention provides a method for detecting cancer and a pharmaceutical composition for the treatment and prevention of such cancer. Furthermore, the present invention provides a peptide containing contiguous amino acids derived from an eEF2 protein having a binding ability to an HLA molecule, and a pharmaceutical composition for the treatment and prevention of cancer, which contains such a peptide, particularly, an HLA-A*2402-restricted eEF2 peptide, an HLA-A*0201-restricted eEF2 peptide, or an HLA-A*0206-restricted eEF2 peptide, and a pharmaceutical composition for the treatment and prevention of cancer, which contains such a peptide, and others. The present application claims priority to Japanese Patent Application No. 2009-002608, the whole disclosure of which is incorporated herein by reference.

BACKGROUND ART

Various cancer markers have hitherto been known. However, there are few cancer markers which can diagnose various cancers using one marker, and such cancer markers are intently searched. On the other hand, molecularly-targeted drugs against cancer such as trastuzumab targeting at HER2, imatinib targeting at one of tyrosine kinases, gefitinib targeting at EGFR, and rituximab targeting at a CD20 antigen are now developed continuously, but even now there is no pharmaceutical composition for the treatment and prevention of cancer, which targets at eEF2 known as a translation elongation factor (eukaryotic translation elongation factor 2) (Non-Patent Document 1). Also, search of antigenic proteins is carried out with respect to various cancers, but only a few proteins are proved to be a cancer antigen.

Non-Patent Document 1: Nygard 0, Nilsson L., “Kinetic determination of the effects of ADP-ribosylation on the interaction of eukaryotic elongation factor 2 with ribosomes”, J Biol Chem. 1990; 265:6030-4

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

Thus, an object to be achieved by the present invention is to provide a method for detecting cancer using a protein expressed in various cancers as an indicator, and a pharmaceutical composition for the treatment or prevention of such cancer detected by the method. Another object of the present invention is to provide a pharmaceutical composition containing a cancer antigen peptide derived from such a protein.

Means for Solving the Problems

The present inventors have devoted themselves to much research so as to achieve the above objects. As a result, the present inventors have found one marker protein eEF2 which is highly expressed in various cancer tissues, and accomplished a method for detecting cancer using, as an indicator, expression of the marker protein and an antibody produced in the body against the marker protein and a pharmaceutical composition for the treatment and prevention of such cancer which targets at the eEF2 protein. Also, the present inventors have found that a part of a contiguous amino acid sequence encoding the eEF2 protein functions as a cancer antigen peptide, and proved that such a part can be used in a pharmaceutical composition for the treatment and prevention of such cancer.

Thus, the present invention provides:

(1) A method for detecting cancer in a subject, which comprises the step of determining the presence or amount of an eEF2 polypeptide, an eEF2 antibody or a transcript of an eEF2 gene in a sample obtained from the subject; (2) The method according to (1), wherein the cancer is selected from the group consisting of lung adenocarcinoma, non-small cell lung cancer, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal cancer, esophageal squamous cell cancer, stomach cancer, colon cancer, pancreatic duct cancer, glioblastoma, and malignant lymphoma; (3) A double-stranded siRNA inhibiting cancer cell proliferation, wherein the sense strand consists of the RNA sequence shown in SEQ ID NO:2 and the antisense strand consists of the RNA sequence shown in SEQ ID NO:3; (4) The double-stranded siRNA according to (3), wherein the cancer cell is derived from cancer selected from the group consisting of stomach cancer, lung cancer, pancreatic cancer, glioblastoma and malignant lymphoma; (5) A pharmaceutical composition for the treatment or prevention of cancer, comprising the double-stranded siRNA according to (3) or (4) as an active ingredient; (6) A method for the treatment or prevention of cancer, which comprises administering an effective amount of the pharmaceutical composition according to (5) to a subject; (7) Use of the double-stranded siRNA according to (3) or (4) for the production of a pharmaceutical for the treatment or prevention of cancer; (8) An shRNA inhibiting cancer cell proliferation, which targets at an mRNA transcribed from the DNA sequence shown in SEQ ID NO:18 or 19; (9) A nucleic acid from which the shRNA according to (8) is transcribed, which has the DNA sequence shown in SEQ ID NO:20 or 22; (10) A vector comprising the nucleic acid according to (9); (11) A pharmaceutical composition for the treatment or prevention of cancer, which comprises the shRNA according to (8), the nucleic acid according to (9) or the vector according to (10); (12) A method for the treatment or prevention of cancer, which comprises administering an effective amount of the pharmaceutical composition according to (11) to a subject; (13) Use of the shRNA according to (8), the nucleic acid according to (9) or the vector according to (10) for the production of a pharmaceutical for the treatment or prevention of cancer; (14) A pharmaceutical composition for the treatment or prevention of cancer in an HLA-A*2402-positive subject, comprising an eEF2 peptide having an amino acid sequence composed of contiguous amino acids derived from an eEF2 protein, wherein the amino acid sequence is selected from the group consisting of:

(a) Arg Phe Tyr Ala Phe Gly Arg Val Phe (SEQ ID NO:4); (b) Ala Phe Gly Arg Val Phe Ser Gly Leu (SEQ ID NO:5); (c) Arg Phe Asp Val His Asp Val Thr Leu (SEQ ID NO:6); (d) Ala Tyr Leu Pro Val Asn Glu Ser Phe (SEQ ID NO:7); and

(e) an amino acid sequence having substitution, deletion or addition of one or several amino acids in the amino acid sequences as shown in (a) to (d); (15) The pharmaceutical composition according to (14), wherein the amino acid sequence is Ala Tyr Leu Pro Val Asn Glu Ser Phe (SEQ ID NO:7); (16) A pharmaceutical composition for the treatment or prevention of cancer in a subject, comprising a polynucleotide encoding the peptide according to (14); (17) The pharmaceutical composition according to any one of (14) to (16), wherein the cancer is selected from the group consisting of lung adenocarcinoma, small-cell lung cancer, esophageal cancer, stomach cancer, colon cancer, pancreatic duct cancer, malignant glioblastoma, malignant lymphoma and head-and-neck squamous cell cancer; (18) A method for the treatment or prevention of cancer, which comprises administering an effective amount of the pharmaceutical composition according to any one of (14) to (17) to an HLA-A*2402-positive subject; (19) Use of the peptide according to (14) for the production of a pharmaceutical for the treatment or prevention of cancer; (20) A pharmaceutical composition for the treatment or prevention of cancer in an HLA-A*0201-positive subject, comprising an eEF2 peptide having an amino acid sequence composed of contiguous amino acids derived from an eEF2 protein, wherein the amino acid sequence is selected from the group consisting of:

(a) Arg Leu Met Glu Pro Ile Tyr Leu Val (SEQ ID NO:8); (b) Lys Leu Val Glu Gly Leu Lys Arg Leu (SEQ ID NO:9); (c) Tyr Leu Asn Glu Ile Lys Asp Ser Val (SEQ ID NO:10); (d) Ile Leu Thr Asp Ile Thr Lys Gly Val (SEQ ID NO:11); (e) Leu Met Met Tyr Ile Ser Lys Met Val (SEQ ID NO:12); (f) Lys Leu Pro Arg Thr Phe Cys Gln Leu (SEQ ID NO:13); (g) Leu Ile Leu Asp Pro Ile Phe Lys Val (SEQ ID NO:14); and

(h) an amino acid sequence having substitution, deletion or addition of one or several amino acids in the amino acid sequences as shown in (a) to (g); (21) The pharmaceutical composition according to (20), wherein the amino acid sequence is Arg Leu Met Glu Pro Ile Tyr Leu Val (SEQ ID NO:8) or Ile Leu Thr Asp Ile Thr Lys Gly Val (SEQ ID NO:11); (22) The pharmaceutical composition according to (20), wherein the amino acid sequence has, in the Leu Ile Leu Asp Pro Ile Phe Lys Val (SEQ ID NO:14), a substitution of the amino acid Ile at position 2 with Leu or Met, and/or a substitution of the amino acid Val at position 9 with Leu; (23) A pharmaceutical composition for the treatment or prevention of cancer in a subject, comprising a polynucleotide encoding the peptide according to (20); (24) The pharmaceutical composition according to any one of (20) to (23), wherein the cancer is selected from the group consisting of lung adenocarcinoma, small-cell lung cancer, esophageal cancer, stomach cancer, colon cancer, pancreatic duct cancer, malignant glioblastoma, malignant lymphoma and head-and-neck squamous cell cancer; (25) A method for the treatment or prevention of cancer, which comprises administering an effective amount of the pharmaceutical composition according to any one of (20) to (24) to a subject; and (26) Use of the peptide according to (20) for the production of a pharmaceutical for the treatment or prevention of cancer.

Effects of the Invention

According to the present invention, it is possible to detect, in a subject having cancer, or a possibility of cancer, or a prognosis of cancer, various cancers, for example, lung adenocarcinoma, non-small cell lung cancer, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal cancer, esophageal squamous cell cancer, stomach cancer, colon cancer, pancreatic duct cancer, glioblastoma, malignant lymphoma and the like in a high sensitivity. Also, it is possible to inhibit proliferation of cancer cells detected by the above method. Furthermore, the present invention provides an HLA-A*2402-restricted eEF2 peptide or an HLA-A*0201-restricted eEF2 peptide, a pharmaceutical composition for the treatment and prevention of cancer, which comprises such a peptide, and others. Accordingly, it is possible to induce eEF2-specific CTL in vivo and in vitro in a subject having HLA-A*2402 or HLA-A*0201. In particular, since about 55% of Japanese have at least one HLA-A*2402 molecule, and about 19.9% have at least one HLA-A*0201 molecule, it is possible to induce the eEF2-specific CTL in a very wide range of subjects.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows that an eEF2 IgG antibody was detected in sera from lung cancer patients.

FIG. 2 shows the results of immunostaining with an anti-eEF2 antibody in lung tissue sections obtained from patients having non-small cell lung cancer (left) and small-cell lung cancer (right).

FIG. 3 shows the results of immunostaining with an anti-eEF2 antibody in tissue sections of head-and-neck squamous epithelium and esophageal squamous epithelium obtained from patients having head-and-neck squamous cell cancer (left) and esophageal squamous cell cancer (right).

FIG. 4 shows the results of immunostaining with an anti-eEF2 antibody in stomach and large colon tissue sections obtained from patients having stomach cancer (left) and colon cancer (right).

FIG. 5 shows the detection of an eEF2 antibody in sera obtained from patients having various types of cancers and healthy subjects.

FIG. 6 shows that, in patients having non-small cell lung cancer, subjects indicating a high eEF2 antibody titer in sera have a good prognosis.

FIG. 7 shows that the double-stranded siRNA targeting at an mRNA of an eEF2 gene inhibits proliferation of stomach cancer cell lines.

FIG. 8 shows that the double-stranded siRNA targeting at an mRNA of an eEF2 gene inhibits cell proliferation of various cancer cell lines.

FIG. 9 shows the cytotoxic activity of CTL induced using an eEF² ₇₈₆₋₇₉₄ peptide.

FIG. 10 shows the cytotoxic activity of CTL induced using an eEF2₇₈₆₋₇₉₄ peptide against endogenous eEF2 gene-expressing cells.

FIG. 11 is a graph showing the results obtained by analyzing interferon-γ induced using an eEF2₇₃₉₋₇₄₇ peptide by FACS.

FIG. 12 is a graph showing the results obtained by analyzing interferon-γ induced using an eEF2₆₆₄₋₆₆₉ peptide by FACS.

FIG. 13 is a graph showing that forced expression of an eEF2 protein accelerates progression of G2/M phase in a cell cycle.

FIG. 14 is a graph showing that forced expression of an eEF2 protein accelerates tumorigenesis in vivo.

FIG. 15 is a graph showing that forced expression of an eEF2 protein accelerates tumorigenesis in vivo.

FIG. 16 is a graph showing a cytotoxic activity of CTL induced using an eEF2₇₃₉₋₇₄₇ peptide.

FIG. 17 is a graph showing a cytotoxic activity of CTL induced using an eEF2₅₄₉₋₅₂₇ peptide.

FIG. 18 is a graph showing a cytotoxic activity of CTL induced using an eEF2₆₇₄₋₆₇₉ peptide.

FIG. 19 is a graph showing a cytotoxic activity of CTL induced using an eEF2₆₆₁₋₆₆₉ peptide.

FIG. 20 is a graph showing a cytotoxic activity of CTL induced using an eEF2₃₉₄₋₄₀₂ peptide.

FIG. 21 is a graph showing a cytotoxic activity of CTL induced using an eEF2₂₈₄₋₂₉₂ peptide.

FIG. 22 is a graph showing a cytotoxic activity of CTL induced using an eEF2₂₉₂₋₃₀₀ peptide.

FIG. 23 is a graph showing a cytotoxic activity of CTL induced using an eEF2₂₉₂₋₃₀₀ 2L peptide.

FIG. 24 is a graph showing a cytotoxic activity of CTL induced using an eEF2₂₉₂₋₃₀₀ 2M peptide.

FIG. 25 is a graph showing a cytotoxic activity of CTL induced using an eEF2₂₉₂₋₃₀₀ 2L9L peptide.

FIG. 26 is a graph showing the results obtained by measuring the interferon-γ activity when pulsed with an eEF2₂₉₂₋₃₀₀ peptide or modified-type eEF2₂₉₂₋₃₀₀ peptides (eEF2₂₉₂₋₃₀₀ 2L, eEF2₂₉₂₋₃₀₀ 2M, and eEF2₂₉₂₋₃₀₀ 2L9L peptide).

FIG. 27 is a graph showing inhibition of cancer cell proliferation by novel shRNAs of eEF2 in vitro. The cell count is shown using percentage (%) of the count of cells into which vectors expressing shRNA of eEF2 are introduced, relative to the count of cells into which control vector shLuc is introduced.

FIG. 28 is a graph showing the results obtained by measuring the interferon-γ activity when pulsed with a modified-type eEF2₂₉₂₋₃₀₀ peptide (eEF2₂₉₂₋₃₀₀ 2M9L peptide).

FIG. 29 is a graph showing the results of interferon-γ activity measurement indicating that seven eEF2 peptides (eEF2₂₉₂₋₃₀₀ peptide, eEF2₇₃₉₋₇₄₇ peptide, eEF² ₅₁₉₋₅₂₇ peptide, eEF2₆₇₁₋₆₇₉ peptide, eEF2₆₆₁₋₆₆₉ peptide, eEF2₃₉₄₋₄₀₂ peptide, and eEF2₂₈₄₋₂₉₂ peptide) also serve as an HLA-A*0206-restricted peptide.

FIG. 30 is a graph showing the results obtained by measuring the interferon-γ activity when pulsed with three eEF2 peptides (eEF2₄₀₉₋₄₁₇ peptide, eEF2₄₁₂₋₄₂₀ peptide, and eEF2₇₀₁₋₇₀₉ peptide).

BEST MODE FOR CARRYING OUT THE INVENTION

In an aspect, the present invention provides a method for detecting cancer. Subjects in which cancer can be detected using the method of the present invention may be any animals such as, for example, human, monkey, mouse, rat, hamster, guinea pig, bovine, horse, sheep, goat, pig, dog, cat, and rabbit, and most preferably human. Although the present method can be used even if subject animals are healthy, it is preferably used in subjects having cancer or a possibility of cancer. Also, the present method can be used in prognosis of cancer treatment in subjects. Characteristics of the present invention reside in the fact that it can detect cancer in early stage as compared with CEA used as a conventional cancer marker. For example, the method of the present invention can detect non-small cell lung cancer in early stage, particularly in stage I, in a high sensitivity. In this connection, the stage I refers to a stage representing a tumor state classified into T1 or T2, N0 and M0 in the TNM classification defined by the Union for International Cancer Control which is disease stage classification of malignant tumors.

The present invention can be practiced using samples obtained from the above subjects. The samples used in the present invention may be any samples, and it is possible to use tissues containing cells, for example. The samples used in the present invention are preferably various types of tissue sections or sera. The samples can be acquired from subjects using techniques conventional to those skilled in the art. In case tissue sections are used as the samples used in the present invention, for example, tissues obtained by surgery or biopsy may be fixed overnight in 10% formalin, and then embedded in paraffin to prepare thin-sliced sections. On the other hand, in case sera are used as the samples used in the present invention, peripheral blood of subjects may be coagulated in a test tube containing a separating agent, and then, sera may be acquired by centrifugation.

Cancers which can be detected by the method of the present invention include any cancers expressing an eEF2 protein, and are preferably lung adenocarcinoma, non-small cell lung cancer, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal cancer, esophageal squamous cell cancer, stomach cancer, colon cancer, pancreatic duct cancer, glioblastoma, and malignant lymphoma. In particular, lung adenocarcinoma, small-cell lung cancer, stomach cancer, colon cancer, and malignant lymphoma are preferably detected. Cancers detected in the present invention may be those in any stages. For example, cancers in any stage of stage I, stage II and stage III in the TNM classification defined by the above International Union Against Cancer may be detected. A cancer which can be detected by the method of the present invention particularly early stage is non-small cell lung cancer.

When the detection method of the present invention is practiced in a subject, the presence or amount of an eEF2 polypeptide can be determined in the above samples. The eEF2 polypeptide in the present invention means a polypeptide having an amino acid sequence of an eEF2 protein or a partial sequence thereof, and includes the following variants. Thus, the eEF2 polypeptide in the present invention may have the amino acid sequence of a human eEF2 protein shown in SEQ ID NO:1; or may have an amino acid sequence having deletion, substitution or addition of one or several amino acids in the amino acid sequence shown in SEQ ID NO:1, or an amino acid sequence having deletion, substitution, addition and/or insertion of one or multiple amino acids in the amino acid sequence shown in SEQ ID NO:1, for example, an amino acid sequence having deletion, substitution or addition of 1 to 9, preferably 1 to 5, 1 to 4, 1 to 3, more preferably 1 to 2 amino acids, and still more preferably one amino acid, or an amino acid sequence having deletion, substitution, addition and/or insertion of 1 to 9, preferably 1 to 5, 1 to 4, 1 to 3, more preferably 1 to 2 amino acids, and still more preferably one amino acid; or an amino acid sequence having a homology of 70% or more, preferably a homology of 80% or more, more preferably a homology of 90% or more, and still more preferably a homology of 93%, 95%, or 99% or more as compared with the amino acid sequence shown in SEQ ID NO:1; or an amino acid sequence of a fragment of any one of the above amino acid sequences. The homology of an amino acid sequence can be determined using a conventional sequence analyzing tool such as FASTA and BLAST. The fragment in the present invention refers to a portion of the above eEF2 polypeptides. Also, the eEF2 polypeptide in the present invention includes polypeptides which have properties comparable to those of the eEF2 protein and which have an amino acid sequence encoded by a nucleotide sequence hybridizing with a nucleotide sequence encoding the amino acid sequence shown in SEQ ID NO:1 under a stringent condition. The comparable properties in the present specification refer to biologically, chemically and physically comparable properties as compared with the eEF2 protein. The eEF2 protein in the present invention is derived from human. Even if, however, the eEF2 protein is derived from other animals such as, for example, mouse, monkey, rat, bovine and cat, the eEF2 protein in these animals is included in the eEF2 protein in the present specification.

In the present invention, the conditions of the above hybridization can be selected suitably by those skilled in the art according to the description of J. Sambrook et al., “Molecular Cloning: A Laboratory Manual, Second Edition”, 1989, Cold Spring Harbor Laboratory Press. Although the conditions of the hybridization may be a low stringent condition, a high stringent condition is preferable. The low stringent condition is, for example, a condition of 42° C., 0.1×SSC and 0.1% SDS, preferably a condition of 50° C., 0.1×SSC and 0.1% SDS, in a washing step after hybridization in accord with the above reference. The high stringent condition includes, for example, a condition of 65° C., 5×SSC and 0.1% SDS, etc. However, those skilled in the art can realize similar conditions by suitably selecting the above elements.

The detection method of the present invention may be carried out by any methods. For example, the detection method of the present invention can be carried out using an antibody against the above eEF2 polypeptide. An antibody against a polypeptide having an amino acid sequence in an arbitrary region of the above eEF2 polypeptide may be used in the detection method of the present invention. For example, an antibody against a polypeptide having a region of positions 1-417 or positions 411-858 in the amino acid sequence of the human eEF2 protein may be used. The antibody used in the present invention may be any isotype of IgG, IgA, IgM, IgD and IgE. Also, the antibody used in the present invention may be a monoclonal antibody or a polyclonal antibody. The antibody used in the present invention may be prepared using a conventional technique, or may be a marketed product.

Also, the detection method of the present invention can be carried out using an antibody against an eEF2 antibody. The eEF2 antibody which can be detected in the present invention is one produced in vivo, i.e., in the body of a subject. In the detection method of the present invention, an antibody against the above eEF2 antibody can be prepared by a known technique, or may be a marketed product. Preferably, an anti-eEF2 antibody (H-118, Santa Cruz Biotechnology, Santa Cruz, Calif.) may be used.

In order to determine the presence or amount of an eEF2 polypeptide or an eEF2 antibody in a sample, known means and methods can be used in the present invention. Any means and methods may be used so far as they can detect qualitatively or quantitatively an eEF2 polypeptide or an eEF2 antibody. For example, they include immunological detection methods for a protein such as immunostaining, dot blotting, fluorescence antibody technique, complement-binding reaction, neutralizing antibody measurement, immunoprecipitation, western blotting, radioimmunoassay (RIA), ELISA, and two-hybrid system. Preferably, immunostaining or dot blotting may be used in the present invention.

“Positive” evaluation can be determined in the detection method of the present invention by comparing the presence or amount of an eEF2 polypeptide or an eEF2 antibody in a sample obtained from a subject with the presence or amount of the eEF2 polypeptide or eEF2 antibody in a sample obtained from a healthy subject or a subject in a normal phase. In case a serum is used as a sample in the detection method of the present invention, an antibody titer (densitometric units) of an eEF2 antibody in the serum may be used as an indicator. In this case, an antibody titer of an eEF2 antibody in a serum of a subject is measured by dot blotting, and a numerical value higher than that in a serum from a healthy subject, preferably 1,000 or more, more preferably 2,000 or more of an antibody titer (densitometric units) may be determined as “positive”. However, the numerical value can vary depending on various factors such as cancer types and tissues, and can be set suitably by those skilled in the art. On the other hand, in case a tissue section is used as a sample, a degree of stain by immunostaining in the tissue section may be used as a criterion. In this case, for example, the presence of cancer cells showing intense stain as compared with corresponding normal cells in an amount of 25% or more of total cancer cells may be determined as “positive”. However, the determination may be made suitably by those skilled in the art.

When the detection method of the present invention is practiced in a subject, the presence or amount of a transcript of an eEF2 gene can be determined in a sample. The transcript of an eEF2 gene in the present invention means a product transcribed from a nucleotide sequence encoding an amino acid sequence of the above eEF2 polypeptide or a fragment thereof, and may be, for example, mRNAs or any other types of RNAs as well as their fragments, etc. Also, the presence or amount of a polynucleotide having a nucleotide sequence (for example, DNA sequence) encoding an amino acid sequence of an eEF2 polypeptide or a fragment thereof can be determined in the detection method of the present invention.

In order to determine the presence or amount of the above transcript or polynucleotide in a sample, means and methods conventional to those skilled in the art as a method for detecting a polynucleotide may be used in the present invention. For example, they include methods for detecting a polynucleotide such as in situ hybridization, northern blotting, southern blotting, dot blotting, RNase protection assay, PCR, RT-PCR, and real-time PCR. Also, it may be possible to carry out a gene analyzing method using a microarray (for example, DNA microarray, microRNA microarray, protein microarray, etc.). Furthermore, other methods may be used so far as they can detect the above transcript or polynucleotide qualitatively or quantitatively.

Furthermore, the method of the present invention can be used for diagnosis of prognosis of a subject having cancer. Cancers to which the method of the present invention can be applied may be any cancers expressing an eEF2 protein as described above, and they are preferably lung adenocarcinoma, non-small cell lung cancer, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal cancer, esophageal squamous cell cancer, stomach cancer, colon cancer, pancreatic duct cancer, glioblastoma, malignant lymphoma, and more preferably non-small cell cancer. In the diagnosis of prognosis in the present invention, the higher the value of an antibody titer of an eEF2 antibody in a sample obtained from a subject, the better the prognosis. For example, the antibody titer (densitometric units) of the eEF2 antibody is a value of 1,000 or more, preferably 2,000 or more, and more preferably 4,000 or more, and those skilled in the art can suitably determine the value taking various factors into account.

In another aspect, the present invention relates to a diagnosis kit for detecting cancer, which comprises, as an essential constituent, an antibody against the above eEF2 polypeptide or eEF2 antibody, or a polynucleotide probe complementary to the above transcript of eEF2 gene or a portion thereof. In the present invention, the above antibody or probe is preferably labeled. The above labeling can be carried out by a conventional method. The kit of the present invention contains, for example, a reagent essential to a method for detecting a protein or a polynucleotide, a sampling means, a reaction vessel and the like, in addition to the antibody against the above eEF polypeptide or eEF2 antibody, or the polynucleotide probe complementary to the above transcript of eEF2 gene or a portion thereof. In general, the kit is accompanied with an instruction manual. The kit of the present invention can be used to detect efficiently cancer expressing an eEF2 protein in a serum or a tissue.

In another aspect, the present invention relates to a double-stranded siRNA which inhibits cancer cell proliferation. Cancer cells of which proliferation can be inhibited by the present invention may be any cancers expressing an eEF2 protein, and are preferably lung adenocarcinoma, non-small cell lung cancer, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal cancer, esophageal squamous cell cancer, stomach cancer, colon cancer, pancreatic duct cancer, glioblastoma, and malignant lymphoma. In particular, lung adenocarcinoma, small-cell lung cancer, stomach cancer, colon cancer, and malignant lymphoma are preferably inhibited.

The siRNA of the present invention is a double-stranded siRNA containing a sense strand and an antisense strand targeting at a nucleotide sequence of an mRNA transcribed from a human eEF2 gene. The nucleotide sequence targeted by the siRNA of the present invention may be a partial sequence of a nucleotide sequence encoding the amino acid sequence shown in SEQ ID NO:1. The siRNA of the present invention is preferably a double-stranded siRNA consisting of the sense strand (SEQ ID NO:2) and the antisense strand (SEQ ID NO:3) having the RNA sequences as shown below:

Sense strand of siRNA of the present invention (SEQ ID NO:2);

5′-CAUGGGCAACAUCAUGAUCGAUCCUGUCCU-3′

Antisense strand of siRNA of the present invention (SEQ ID NO:3);

5′-AGGACAGGAUCGAUCAUGAUGUUGCCCAUG-3′.

Although preferred RNA sequences of the siRNA of the present invention are the above sequences shown in SEQ ID NOs:2 and 3, these sequences may have addition, deletion or substitution of one, two or three bases. Also, these sequences may have substitution, deletion, addition and/or insertion of 1 to 3, preferably 1 or 2 bases, and more preferably one base. The hybridization condition in this case is a condition in a living body in case the siRNA of the present invention is used by administering in a living body, and a moderately stringent condition or a high stringent condition in case the siRNA of the present invention is used in vitro as a reagent. Such a condition includes, for example, a hybridization condition of 400 mM NaCl, 40 mM PIPES pH6.4, 1 mM EDTA, at 50° C. to 70° C. for 12 to 16 hours. Also, the sense strand sequence of the siRNA of the present invention has a sequence homology of 90% or more, preferably 95% or more, and more preferably 95, 96, 97, 98, or 99% or more to a target sequence.

Also, the siRNA of the present invention may have addition of an overhang sequence at 5′ end or 3′ end. In this connection, the overhang sequence refers to a protruding sequence added to either 5′ end or 3′ end of a double-stranded sequence consisting of paired sense and antisense strands in order to increase a stability of the double-stranded siRNA. The overhang sequence includes, for example, a sequence such as AG, UA, AUG, UUG and AAGCUU from 5′ side, and any sequences can be used. In the double-stranded siRNA of the present invention, UU is preferably added to the 3′ end of sense and antisense strands. Also, the above double-stranded siRNA of the present invention may form an shRNA by linking two siRNAs through a loop sequence.

The double-stranded siRNA of the present invention can be prepared by a method conventional to those skilled in the art. For example, it may be synthesized in vitro chemically or enzymatically, or synthesized in vivo, but the method is not limited thereto. A chemically synthesizing method is preferably used. After each strand is synthesized by such a synthetic method, the strands can be paired under a conventional pairing condition. When used, the strands may be purified suitably as needed. Also, the double-stranded siRNA of the present invention may be prepared in the form of a siRNA expression vector expressing the above RNA sequences of the siRNA (SEQ ID NO:2 and SEQ ID NO:3). In this case, for example, tRNA-shRNA expression vector, piGENE tRNA Pur (Clontech, Palo Alto, Calif.) may be used for the preparation. There is no particular limitation on the length of the siRNA used in the present invention, and 15 to 50 mer siRNA can be exemplified as an example of a preferred siRNA of the present invention, 20 to 40 mer siRNA as a more preferred example, and 25 to 35 mer (for example, 30 mer) siRNA as further preferred example. Thus, a double-stranded siRNA which can hybridize with the sequence: 5′-CAUGGGCAACAUCAUGAUCGAUCCUGUCCU-3′ (SEQ ID NO:2) of the eEF2 mRNA and which is 15 to 50 mer, preferably 20 to 40 mer, more preferably 25 to 35 mer (for example, 30 mer) in length of each siRNA can be exemplified as an example of a preferred siRNA of the present invention.

In general, it is known that a siRNA binds to an mRNA of a target gene in cells into which the siRNA is introduced and inhibits expression of the mRNA. Accordingly, the double-stranded siRNA of the present invention has a function of inhibiting expression of an eEF2 gene, thereby being able to inhibit cell proliferation in a subject into which the siRNA is introduced. Methods for introducing or administering the siRNA in the present invention may be those known to those skilled in the art such as a calcium phosphate method using a transfection reagent, a liposome method, a non-liposome method, electroporation, and a magnetic particle method. Alternatively, a method may be adopted in which the siRNA is integrated into a conventional siRNA expression vector and the vector is introduced by a known method as described above. Preferably, a siRNA expression vector expressing the above RNA sequences of the siRNA (SEQ ID NO:2 and SEQ ID NO:3) is introduced by a known method. Also, the siRNA of the present invention may be administered in the form of a pharmaceutical composition as described below.

The present invention provides a pharmaceutical composition for the treatment or prevention of cancer, comprising the above double-stranded siRNA as an active ingredient. The pharmaceutical composition of the present invention may contain a known anticancer drug as an active ingredient, in addition to the above double-stranded siRNA.

The pharmaceutical composition of the present invention may contain a siRNA as an active ingredient in the form of a vector into which the siRNA is integrated. For example, the siRNA may be contained in the form of one cloned into a known siRNA expression vector such as a commercially available siRNA expression vector or a known siRNA expression vector suitably recombined according to an aspect used. Accordingly, the present invention provides a nucleic acid encoding the siRNA of the present invention, and a vector containing the nucleic acid.

The pharmaceutical composition of the present invention may contain a pharmaceutically acceptable carrier. The pharmaceutically acceptable carrier which can be used in the present invention may be one or more components selected from the group consisting of a physiological saline, distilled water, Ringer's solution, a buffered physiological saline, a dextrose solution, a maltodextrose solution, glycerol, ethanol and a liposome, but is not limited thereto. Also, other conventional additives such as an antioxidant, a buffered aqueous solution, and a bacteriostatic agent may be added to the pharmaceutical composition of the present invention. Furthermore, diluents, sprays, surfactants, binders and lubricants may be added to the composition in order to produce an injection solution, pills, capsules, granules or tablets.

The dosage form of the pharmaceutical composition of the present invention may be oral administration or parenteral administration (for example, intravenous administration, intradermal administration, subcutaneous administration, intramuscular administration, transnasal administration or oral administration), and other dosage forms may also be used so far as they can deliver an active ingredient efficiently to an affected part or its neighborhood. The effective amount of the siRNA of the present invention administered through the pharmaceutical composition of the present invention can be determined depending on conditions of subjects such as, for example, weight, age, sex and health state of subjects, as well as amount of food, frequency of administration, method of administration, amount of excretion, seriousness of disease and the like. The effective amount of the siRNA of the present invention administered through the pharmaceutical composition of the present invention is usually from 0.01 to 100 mg/kg per day, and preferably from 0.1 to 10 mg/kg per day.

In another aspect, the present invention relates to a method for the treatment or prevention of cancer, which comprises administering an effective amount of the above pharmaceutical composition to a subject. The cancers to be treated or prevented may be any cancers so far as they express an eEF2 protein, and include, for example, lung adenocarcinoma, non-small cell lung cancer, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal cancer, esophageal squamous cell cancer, stomach cancer, colon cancer, pancreatic duct cancer, glioblastoma, and malignant lymphoma. Preferably, the composition of the present invention may be administered to a subject who is determined as “positive” by the above method for detecting cancer.

In still another aspect, the present invention relates to use of the above double-stranded siRNA for the production of a pharmaceutical for the treatment or prevention of cancer.

In still another aspect, the present invention relates to an shRNA or siRNA which inhibits cancer cell proliferation. In general, the shRNA (short hairpin RNA or small hairpin RNA) is an RNA in which a sense strand and an antisense strand are linked through a loop sequence, and may produce a double-stranded siRNA by intracellular cleavage of the loop structure. The siRNA of the present invention is preferably a double-stranded siRNA. There is no particular limitation on regions in the eEF2 targeted by the shRNA or siRNA of the present invention, and an shRNA or siRNA can be exemplified as a preferred example which targets at an mRNA transcribed from the following DNA sequence: 5′-gcc tggccgagga catcgataaa ggcgagg-3′ (SEQ ID NO:18); or 5′-actcaac cataacactt gatgccgttt ctt-3′ (SEQ ID NO:19). The shRNA of the present invention may be one transcribed from a vector containing a DNA sequence consisting of sense sequence-loop sequence-antisense sequence of the above DNA sequence. When transcribed from a vector containing such a DNA sequence to an RNA, RNAs derived from a sense sequence and an antisense sequence bind to each other to form a short hairpin RNA, and are stabilized. In this connection, the loop sequence used in the present invention may be any sequences, which can be selected suitably by those skilled in the art. An siRNA which can hybridize with an mRNA transcribed from 5′-gcc tggccgagga catcgataaa ggcgagg-3′ (SEQ ID NO:18) or 5′-actcaac cataacactt gatgccgttt ctt-3′ (SEQ ID NO:19) can be exemplified as a preferred example of the siRNA of the present invention. An siRNA which has a sequence complementary to an mRNA transcribed from 5′-gcc tggccgagga catcgataaa ggcgagg-3′ (SEQ ID NO:18) or 5′-actcaac cataacactt gatgccgttt ctt-3′ (SEQ ID NO:19) can be mentioned as a more specific example of the siRNA of the present invention. Alternatively, the siRNA of the present invention may be a double-stranded siRNA composed of a sense strand and an antisense strand of an mRNA corresponding to the DNA sequence shown in SEQ ID NO:18 or 19. An shRNA containing an RNA which can hybridize with an mRNA transcribed from 5′-gcc tggccgagga catcgataaa ggcgagg-3′ (SEQ ID NO:18) and an RNA which can hybridize with the RNA can be exemplified as a preferred example of the shRNA of the present invention. Also, an shRNA containing an RNA which can hybridize with an mRNA transcribed from 5′-actcaac cataacactt gatgccgttt ctt-3′ (SEQ ID NO:19) and an RNA which can hybridize with the RNA can be exemplified as a preferred example of the shRNA of the present invention. An shRNA can be mentioned as a more specific example of the shRNA of the present invention, which is transcribed from a nucleic acid having the following DNA sequence:

(SEQ ID NO: 20) 5′-gcc tggccgagga catcgatgaa agcgtgg cttcctgtca cctcgcc tttatcgatg tcctcggcca ggc-3′; (SEQ ID NO: 22) 5′-actcaac cataacactt gataccattt gtt cttcctgtca aag aaacggcatc aagtgttatg gttgagt-3′; (SEQ ID NO: 21) 3′-cgg accggctcct gtagctactt tcgcacc gaaggacagt ggagcgg aaatagctac aggagccggt ccg-5′; or (SEQ ID NO: 23) 3′-tgagttg gtattgtgaa ctatggtaaa caa gaaggacagt ttc tttgccgtag ttcacaatac caactca-5′.

In the present invention, the above DNA sequence or RNA sequence may have addition, deletion or substitution of 1, 2, or 3 bases. Alternatively, the sequence in the present invention may have a sequence homology of 90% or more, preferably 95% or more, and more preferably 95, 96, 97, 98, or 99% or more to the above DNA sequence or RNA sequence. In this connection, the homology, condition of hybridization, and length of the siRNA are as described above. Also, in the present invention, the above DNA sequence or RNA sequence may have addition, deletion, substitution and/or insertion of 1, 2, or 3 bases.

The shRNA or siRNA of the present invention can be prepared by a method conventional to those skilled in the art. For example, it may be synthesized in vitro chemically or enzymatically, or synthesized in vivo, but the method is not limited thereto. Also, the shRNA or siRNA of the present invention may be prepared in the form of an shRNA expression vector or a siRNA expression vector containing a DNA sequence as shown in the above SEQ ID NO:20 or 22. In this case, for example, tRNA-shRNA expression vector, piGENE tRNA Pur (Clontech, Palo Alto, Calif.) may be used for the preparation.

Methods for introducing or administering the shRNA or siRNA of the present invention may be those known to those skilled in the art such as a calcium phosphate method using a transfection reagent, a liposome method, a non-liposome method, electroporation, and a magnetic particle method. Alternatively, a method may be adopted in which the RNA is integrated into a conventional siRNA expression vector and the vector is introduced by a known method as described above. The shRNA or siRNA of the present invention may be administered in the form of a pharmaceutical composition as described below.

The present invention provides a pharmaceutical composition for the treatment or prevention of cancer, comprising the above shRNA or siRNA as an active ingredient. The pharmaceutical composition of the present invention may also contain a known anticancer drug.

The pharmaceutical composition of the present invention may contain a nucleic acid encoding the shRNA or siRNA of the present invention (for example, a nucleic acid containing a DNA sequence shown in SEQ ID NO:20 or 22) as an active ingredient. For example, the nucleic acid may be one in which a nucleic acid containing such a DNA sequence is integrated into a commercially available shRNA expression vector or siRNA expression vector. Thus, the present invention provides a nucleic acid encoding the shRNA or siRNA of the present invention, and a vector containing the nucleic acid.

The pharmaceutical composition of the present invention may contain pharmaceutically acceptable conventional carriers and additives. The dosage form of the pharmaceutical composition of the present invention may be oral administration or parenteral administration (for example, intravenous administration, intradermal administration, subcutaneous administration, intramuscular administration, transnasal administration or oral administration). Also, the effective amount of the shRNA or siRNA of the present invention administered through the pharmaceutical composition of the present invention can be determined depending on conditions of subjects such as, for example, weight, age, sex and health state of subjects, as well as amount of food, frequency of administration, method of administration, amount of excretion, seriousness of disease and the like.

In another aspect, the present invention relates to a method for the treatment or prevention of cancer, which comprises administering an effective amount of the above pharmaceutical composition to a subject. Cancers to be treated or prevented may be any cancers so far as they express an eEF2 protein, and include, for example, lung adenocarcinoma, non-small cell lung cancer, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal cancer, esophageal squamous cell cancer, stomach cancer, colon cancer, pancreatic duct cancer, glioblastoma, and malignant lymphoma.

In still another aspect, the present invention relates to use of the above shRNA or siRNA for the production of a pharmaceutical for the treatment or prevention of cancer.

In a further aspect, the present invention relates to a peptide containing contiguous amino acids derived from an eEF2 protein. Examples of the peptide of the present invention are peptides containing an amino acid sequence as described below or peptides consisting of an amino acid sequence described below. Preferably, these peptides have a binding ability to an HLA molecule. Also, these peptides preferably induce a cytotoxic activity. Moreover, these peptides are preferably an HLA-A*2402-restricted eEF2 peptide, an HLA-A*0201-restricted eEF2 peptide, or an HLA-A*0206-restricted eEF2 peptide. Furthermore, these peptides preferably have a length of 9 to 30 amino acids. In addition, the present invention provides a pharmaceutical composition for the treatment or prevention of cancer which comprises these peptides, use of these peptides for the production of a pharmaceutical for the treatment or prevention of cancer, a method for the treatment or prevention of cancer, which comprises administering these peptides to a subject, and others.

Thus, in one aspect, the present invention provides an HLA-A*2402-restricted eEF2 peptide. Also, the present invention provides an HLA-A*2402-restricted eEF2 peptide for the treatment or prevention of cancer in an HLA-A*2402-positive subject, as well as a pharmaceutical composition containing the same. An exemplary HLA-A*2402-restricted eEF2 peptide used in the present invention is a peptide having an amino acid sequence composed of contiguous amino acids derived from an eEF2 protein or a peptide containing an amino acid sequence composed of contiguous amino acids derived from an eEF2 protein, wherein the above amino acid sequence is selected from the group consisting of:

(SEQ ID NO: 4) Arg Phe Tyr Ala Phe Gly Arg Val Phe; (SEQ ID NO: 5) Ala Phe Gly Arg Val Phe Ser Gly Leu; (SEQ ID NO: 6) Arg Phe Asp Val His Asp Val Thr Leu; (SEQ ID NO: 7) Ala Tyr Leu Pro Val Asn Glu Ser Phe; and an amino acid sequence having substitution or deletion or addition of several amino acids, for example, 1 to 9, preferably 1 to 5, 1 to 4, 1 to 3, more preferably 1 to 2 amino acids, and still more preferably one amino acid in one of the above amino acid sequences; but is not limited to these peptides. Also, a peptide may be contained wherein the above amino acid sequence is selected from the group consisting of amino acid sequences having substitution, deletion, addition and/or insertion of several amino acids, for example, 1 to 9, preferably 1 to 5, 1 to 4, 1 to 3, more preferably 1 to 2 amino acids, and still more preferably one amino acid in one of the above amino acid sequences. In case an amino acid in the above peptides is substituted, preferred substitution sites are an amino acid at position 2 and/or position 9. A preferred example of an amino acid at position 2 in the above peptides is Phe or Tyr. Also, a preferred example of an amino acid at position 9 in the above peptides is Ile, Leu or Phe. Specific examples of such a modified-type peptide are peptides as shown in Table 12 or Table 13. A preferred eEF2 peptide in the present invention is Ala Tyr Leu Pro Val Asn Glu Ser Phe (SEQ ID NO:7). In this regard, however, it is essential for all the above peptides to retain a binding ability to the HLA-A*2402 molecule. In the present specification, a peptide retaining a binding ability to the HLA-A*2402 is referred to as an HLA-A*2402-restricted eEF2 peptide. In addition, the above peptides of the present invention may be used for a subject other than the HLA-A*2402-positive subject. Accordingly, the present invention provides a peptide containing any one of the above amino acid sequences, and a pharmaceutical composition containing the peptide.

In another aspect, the present invention provides an HLA-A*0201-restricted eEF2 peptide. Also, the present invention provides a pharmaceutical composition for the treatment or prevention of cancer in an HLA-A*0201-positive subject, comprising the HLA-A*0201-restricted eEF2 peptide. The HLA-A*0201-restricted eEF2 peptide used in the present invention is a peptide having an amino acid sequence composed of contiguous amino acids derived from an eEF2 protein or a peptide containing an amino acid sequence composed of contiguous amino acids derived from an eEF2 protein. Candidates of the HLA-A*0201-restricted eEF2 peptide used in the present invention are exemplified in the following Tables 1 to 7. Among them, an example of a preferred peptide in the present invention is a peptide wherein the above amino acid sequence is selected from the group consisting of:

(SEQ ID NO: 8) Arg Leu Met Glu Pro Ile Tyr Leu Val; (SEQ ID NO: 9) Lys Leu Val Glu Gly Leu Lys Arg Leu; (SEQ ID NO: 10) Tyr Leu Asn Glu Ile Lys Asp Ser Val; (SEQ ID NO: 11) Ile Leu Thr Asp Ile Thr Lys Gly Val; (SEQ ID NO: 12) Leu Met Met Tyr Ile Ser Lys Met Val; (SEQ ID NO: 13) Lys Leu Pro Arg Thr Phe Cys Gln Leu; (SEQ ID NO: 14) Leu Ile Leu Asp Pro Ile Phe Lys Val; and an amino acid sequence having substitution or deletion or addition of several amino acids, for example, 1 to 9, preferably 1 to 5, 1 to 4, 1 to 3, more preferably 1 to 2 amino acids, and still more preferably one amino acid in one of the above amino acid sequences; but is not limited to these peptides. Also, a peptide may be contained wherein the above amino acid sequence is selected from the group consisting of amino acid sequences having substitution, deletion, addition and/or insertion of several amino acids, for example, 1 to 9, preferably 1 to 5, 1 to 4, 1 to 3, more preferably 1 to 2 amino acids, and still more preferably one amino acid in one of the above amino acid sequences. Among them, a particularly preferred HLA-A*0201-restricted eEF2 peptide is Arg Leu Met Glu Pro Ile Tyr Leu Val (SEQ ID NO:8) or Ile Leu Thr Asp Ile Thr Lys Gly Val (SEQ ID NO:11). Also, the HLA-A*0201-restricted eEF2 peptide of the present invention may have a substitution of an amino acid, particularly, at position 2 and/or at position 9 with another amino acid. A preferred example of the amino acid at position 2 in the above peptides is Leu or Met. Also, a preferred example of the amino acid at position 9 in the above peptides is Leu or Val. Examples of such a modified-type peptide are shown in Tables 15 to 21. Preferred examples are peptides having, in the Leu Ile Leu Asp Pro Ile Phe Lys Val (SEQ ID NO:14), a substitution of the amino acid Ile at position 2 with Leu or Met, and/or a substitution of the amino acid Val at position 9 with Leu. Particularly preferred examples are Leu Leu Leu Asp Pro Ile Phe Lys Val (SEQ ID NO:15), Leu Met Leu Asp Pro Ile Phe Lys Val (SEQ ID NO:16), Leu Leu Leu Asp Pro Ile Phe Lys Leu (SEQ ID NO:17), or Leu Met Leu Asp Pro Ile Phe Lys Leu (SEQ ID NO:24). In this regard, however, it is essential for all the above peptides to retain a binding ability to the HLA-A*0201 molecule. In the present specification, a peptide retaining a binding ability to the HLA-A*0201 is referred to as an HLA-A*0201-restricted eEF2 peptide. Also, the HLA-A*0201-restricted eEF2 peptide of the present invention may have an action of increasing an interferon-γ activity. In addition, the above peptides of the present invention may be used for a subject other than the HLA-A*0201-positive subject. Accordingly, the present invention provides a peptide containing any one of the above amino acid sequences, and a pharmaceutical composition containing the peptide.

In still another aspect, the present invention provides an HLA-A*0206-restricted eEF2 peptide. Also, the present invention provides a pharmaceutical composition for the treatment or prevention of cancer in an HLA-A*0206-positive subject which comprises the HLA-A*0206-restricted eEF2 peptide. The HLA-A*0206-restricted eEF2 peptide used in the present invention is a peptide having an amino acid sequence composed of contiguous amino acids derived from an eEF2 protein or a peptide containing an amino acid sequence composed of contiguous amino acids derived from an eEF2 protein. A preferred example of the HLA-A*0206-restricted eEF2 peptide used in the present invention is a peptide wherein the above amino acid sequence is selected from the group consisting of:

(SEQ ID NO: 8) Arg Leu Met Glu Pro Ile Tyr Leu Val; (SEQ ID NO: 9) Lys Leu Val Glu Gly Leu Lys Arg Leu; (SEQ ID NO: 10) Tyr Leu Asn Glu Ile Lys Asp Ser Val; (SEQ ID NO: 11) Ile Leu Thr Asp Ile Thr Lys Gly Val; (SEQ ID NO: 12) Leu Met Met Tyr Ile Ser Lys Met Val; (SEQ ID NO: 13) Lys Leu Pro Arg Thr Phe Cys Gln Leu; (SEQ ID NO: 14) Leu Ile Leu Asp Pro Ile Phe Lys Val; and an amino acid sequence having substitution or deletion or addition of several amino acids, for example, 1 to 9, preferably 1 to 5, 1 to 4, 1 to 3, more preferably 1 to 2 amino acids, and still more preferably one amino acid in one of the above amino acid sequences; but is not limited to these peptides. Also, a peptide may be contained wherein the above amino acid sequence is selected from the group consisting of amino acid sequences having substitution, deletion, addition and/or insertion of several amino acids, for example, 1 to 9, preferably 1 to 5, 1 to 4, 1 to 3, more preferably 1 to 2 amino acids, and still more preferably one amino acid in one of the above amino acid sequences. In this regard, however, it is essential for all the above peptides to retain a binding ability to the HLA-A*0206 molecule. In the present specification, a peptide retaining a binding ability to the HLA-A*0206 is referred to as an HLA-A*0206-restricted eEF2 peptide. Also, the HLA-A*0206-restricted eEF2 peptide of the present invention may have an action of increasing an interferon-γ activity. In addition, the above peptides of the present invention may be used for a subject other than the HLA-A*0206-positive subject. Accordingly, the present invention provides a peptide containing any one of the above amino acid sequences, and a pharmaceutical composition containing the peptide.

TABLE 1 Starting residue number (Amino Candidate acid residue peptide number in number Amino acid sequence SEQ ID NO: 1) 1 LILDPIFKV (SEQ ID NO: 14) 292 2 RLMEPIYLV (SEQ ID NO: 8) 739 3 KLVEGLKRL (SEQ ID NO: 9) 519 4 YLNEIKDSV (SEQ ID NO: 10) 671 5 ILTDITKGV (SEQ ID NO: 11) 661 6 LMMYISKMV (SEQ ID NO: 12) 394 7 KLPRTFCQL (SEQ ID NO: 13) 284 8 GLHGWAFTL (SEQ ID NO: 50) 217 9 GLVGVDQFL (SEQ ID NO: 51) 471 10 WLPAGDALL (SEQ ID NO: 52) 343 11 VVVDCVSGV (SEQ ID NO: 53) 127 12 AIAERIKPV (SEQ ID NO: 54) 146 13 IMIDPVLGT (SEQ ID NO: 55) 203 14 RLAKSDPMV (SEQ ID NO: 56) 526 15 GLVSTGLKV (SEQ ID NO: 57) 419

TABLE 2 Starting residue number (Amino Candidate acid residue peptide number in number Amino acid sequence SEQ ID NO: 1) 16 LVGVDQFLA (SEQ ID NO: 58) 472 17 KMDRALLEL (SEQ ID NO: 59) 159 18 FVVKAYLPV (SEQ ID NO: 60) 782 19 TILMMGRYV (SEQ ID NO: 61) 450 20 NLIDSPGHV (SEQ ID NO: 62) 101 21 ALDNFLDKL (SEQ ID NO: 63) 850 22 CLYASVLTA (SEQ ID NO: 64) 728 23 LLQMITIHL (SEQ ID NO: 65) 350 24 QVAGTPMFV (SEQ ID NO: 66) 775 25 VVAGFQWAT (SEQ ID NO: 67) 679 26 LMMNKMDRA (SEQ ID NO: 68) 155 27 NMRVMKFSV (SEQ ID NO: 69) 696 28 NMRVMKFSV (SEQ ID NO: 70) 493 29 AIMDKKANI (SEQ ID NO: 71) 11 30 CVFDWQIL (SEQ ID NO: 72) 812

TABLE 3 Starting residue number (Amino Candidate acid residue peptide number in number Amino acid sequence SEQ ID NO: 1) 31 GIPALDNFL (SEQ ID NO: 73) 847 32 VLNRKRGHV (SEQ ID NO: 74) 762 33 MMGRYVEPI (SEQ ID NO: 75) 453 34 FLVKTGTIT (SEQ ID NO: 76) 478 35 QVVGGIYGV (SEQ ID NO: 77) 754 36 RVTDGALVV (SEQ ID NO: 78) 120 37 FQWATKEGA (SEQ ID NO: 79) 683 38 VAGTPMFVV (SEQ ID NO: 80) 776 39 GLKEGIPAL (SEQ ID NO: 81) 843 40 SVLTAQPRL (SEQ ID NO: 82) 732 41 PMFVVKAYL (SEQ ID NO: 83) 780 42 VMKFSVSPV (SEQ ID NO: 84) 496 43 WAFTLKQFA (SEQ ID NO: 85) 221 44 FEHAHNMRV (SEQ ID NO: 86) 488 45 KQFAEMYVA (SEQ ID NO: 87) 226

TABLE 4 Starting residue number (Amino Candidate acid residue peptide number in number Amino acid sequence SEQ ID NO: 1) 46 RVFSGLVST (SEQ ID NO: 88) 415 47 RIVENVNVI (SEQ ID NO: 89) 180 48 MMNKMDRAL (SEQ ID NO: 90) 156 49 EMYVAKFAA (SEQ ID NO: 91) 230 50 FSVSPVVRV (SEQ ID NO: 92) 499 51 ELYQTFQRI (SEQ ID NO: 93) 173 52 SVVAGFQWA (SEQ ID NO: 94) 678 53 IMNFKKEET (SEQ ID NO: 95) 304 54 GALVVVDCV (SEQ ID NO: 96) 124 55 KVEDMMKKL (SEQ ID NO: 97) 252 56 RNMSVIAHV (SEQ ID NO: 98) 20 57 KANIRNMSV (SEQ ID NO: 99) 16 58 TVSEESNVL (SEQ ID NO: 100) 582 59 GVCVQTETV (SEQ ID NO: 101) 134 60 DITKGVQYL (SEQ ID NO: 102) 664

TABLE 5 Starting residue number (Amino Candidate acid residue peptide number in number Amino acid sequence SEQ ID NO: 1) 61 AVMRRWLPA (SEQ ID NO: 103) 338 62 FSSEVTAAL (SEQ ID NO: 104) 111 63 KLWGDRYFD (SEQ ID NO: 105) 259 64 LEPEELYQT (SEQ ID NO: 106) 169 65 GVDQFLVKT (SEQ ID NO: 107) 474 66 FTLKQFAEM (SEQ ID NO: 108) 223 67 AEMYVAKFA (SEQ ID NO: 109) 229 68 FTADLRSNT (SEQ ID NO: 110) 796 69 MIDPVLGTV (SEQ ID NO: 111) 204 70 YLPVNESFG (SEQ ID NO: 112) 787 71 NPADLPKLV (SEQ ID NO: 113) 513 72 GPAERAKKV (SEQ ID NO: 114) 245 73 DLPKLVEGL (SEQ ID NO: 115) 516 74 MVNFTVDQI (SEQ ID NO: 116) 1 75 GGQAFPQCV (SEQ ID NO: 117) 805

TABLE 6 Starting residue number (Amino acid Candidate residue peptide number in number Amino acid sequence SEQ ID NO: 1) 76 VLTAQPRLM (SEQ ID NO: 118) 733 77 SGLHGWAFT (SEQ ID NO: 119) 216 78 ITIHLPSPV (SEQ ID NO: 120) 354 79 KSTLTDSLV (SEQ ID NO: 121) 32 80 GELHLEICL (SEQ ID NO: 122) 550 81 CITIKSTAI (SEQ ID NO: 123) 67 82 SEVTAALRV (SEQ ID NO: 124) 113 83 FTVDQIRAI (SEQ ID NO: 125) 4 84 AQPRLMEPI (SEQ ID NO: 126) 736 85 YLAEKYEWD (SEQ ID NO: 127) 634 86 KIWCFGPDG (SEQ ID NO: 128) 648 87 GTVGFGSGL (SEQ ID NO: 129) 210 88 VEIQCPEQV (SEQ ID NO: 130) 747 89 KNPADLPKL (SEQ ID NO: 131) 512 90 GVRFDVHDV (SEQ ID NO: 132) 699

TABLE 7 Starting residue number (Amino acid Candidate residue peptide number in number Aminoacidsequence SEQ ID NO: 1) 91 TTFEHAHNM (SEQ ID NO: 133) 486 92 GNIVGLVGV (SEQ ID NO: 134) 467 93 IIPTARRCL (SEQ ID NO: 135) 721 94 PLMMYISKM (SEQ ID NO: 136) 393 95 GQLGPAERA (SEQ ID NO: 137) 242 96 LKQFAEMYV (SEQ ID NO: 138) 225 97 MGNIMIDPV (SEQ ID NO: 139) 200 98 KVFDAIMNF (SEQ ID NO: 140) 299 99 MEPIYLVEI (SEQ ID NO: 141) 741

The peptide used in the present invention is derived from an eEF2 protein, and may consist of the above contiguous amino acid sequence or a modified sequence thereof, or contain such a sequence. In case the peptide contains the above amino acid sequence, there is no particular limitation on the length of the peptide, and the peptide may have any length. Preferred examples of the peptide containing the above contiguous amino acid sequence are peptides having 9 to 30 amino acids, preferably peptides having 9 to 15 amino acids, and more preferably peptides having 9 to 12 amino acids. Thus, the peptide used in the present invention may be, for example, the peptide itself consisting of the above amino acid sequence, or an eEF2 protein containing the above amino acid sequence or a portion thereof. In a peptide used in the present invention, a variety of substances can also be bound to an N-end and/or a C-end of a peptide containing the above amino acid sequence. For example, amino acids, peptides, and analogues thereof may be bound to the peptide. In case these substances are bound to a peptide used in the present invention, they are treated, for example, by an enzyme and the like in the body or through a process such as intracellular processing, and a peptide consisting of the above amino acid sequence is finally produced. The peptide is presented on a cell surface as a complex with an HLA-A*2402 molecule or HLA-A*0201 molecule, thereby being able to produce an induction effect of cytotoxic T cells (CTL). These substances may be those which regulate solubility of a peptide used in the present invention, or improve stability of the peptide (e.g. protease-resistant effect), or, for example, specifically deliver a peptide used in the present invention to a given tissue or organ, or have an enhancing action of an uptake efficiency of antigen-presenting cells and the like. Also, these substances may be a substance which increases an ability to induce the CTL, for example, a helper peptide and the like.

The peptide used in the present invention can be synthesized using a method usually used in this art or a modified method thereof. Such a synthetic method is described, for example, in Peptide Synthesis, Interscience, New York, 1966; The Proteins, Vol. 2, Academic Press Inc., New York, 1976; Peptide Synthesis, Maruzen Company Ltd., 1975; Basis and Experiment of Peptide Synthesis, Maruzen Company Ltd., 1985; Development of Medicine, Sequel, Vol. 14, Peptide Synthesis, Hirokawa Shoten Co., 1991 and others.

Also, the peptide used in the present invention can be prepared using a genetic engineering technique on the basis of the information on a nucleotide sequence encoding the peptide used in the present invention. Such a genetic engineering technique is well known to those skilled in the art.

The present invention relates to a pharmaceutical composition for the treatment or prevention of cancer, comprising the above eEF2 peptide. Since the eEF2 gene is highly expressed, for example, in lung adenocarcinoma, small-cell lung cancer, esophageal cancer, stomach cancer, colon cancer, pancreatic duct cancer, malignant glioblastoma, malignant lymphoma, head-and-neck squamous cell cancer, and the like, the pharmaceutical composition of the present invention can be used for the treatment or prevention of cancer expressing the eEF2 gene. When the pharmaceutical composition of the present invention is administered to an HLA-A*2402- or HLA-A*0201-positive subject, an eEF2-specific CTL is induced by an HLA-A*2402-restricted eEF2 peptide or an HLA-A*0201-restricted eEF2 peptide contained in the pharmaceutical composition, and cancer cells in the subject are impaired by such a CTL.

The pharmaceutical composition of the present invention may contain, for example, carriers, excipients and the like, in addition to the above eEF2 peptide as an active ingredient. Since the HLA-A*2402-restricted eEF2 peptide or HLA-A*0201-restricted eEF2 peptide contained in the pharmaceutical composition of the present invention induces an eEF2-specific CTL, the pharmaceutical composition of the present invention may contain a suitable adjuvant, or may be administered together with a suitable adjuvant in order to enhance its induction efficiency. Preferred adjuvants are, for example, a complete or incomplete Freund's adjuvant, aluminum hydroxide and the like, but are not limited thereto. Also, the pharmaceutical composition of the present invention may contain a known peptide, for example, WT1 peptide and the like, as an active ingredient, in addition to the above eEF2 peptide.

The administration method of the pharmaceutical composition of the present invention can be selected suitably depending on conditions such as types of diseases, a state of subjects, and targeted sites. The method may be, for example, intradermal administration, subcutaneous administration, intramuscular administration, intravenous administration, transnasal administration, or oral administration, but is not limited thereto. Furthermore, the method may be a lymphocyte therapy or a DC (dendritic cell) therapy. The amount of a peptide contained in the pharmaceutical composition of the present invention, dosage form of the pharmaceutical composition, number of doses and the like may be selected suitably depending on conditions such as types of diseases, a state of subjects, and targeted sites. The amount of a peptide administered per one dose is usually from 0.0001 mg to 1000 mg, and preferably from 0.001 mg to 10,000 mg.

In another aspect, the present invention relates to a method for the treatment or prevention of cancer, which comprises administering an effective amount of the above pharmaceutical composition to an HLA-A*2402-positive subject or an HLA-A*0201-positive subject. Cancers to be treated or prevented may be any cancers, and include, for example, lung adenocarcinoma, non-small cell lung cancer, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal squamous cell cancer, stomach cancer, colon cancer, pancreatic duct cancer, glioblastoma and malignant lymphoma.

In still another aspect, the present invention relates to use of an eEF2 peptide for the production of the above pharmaceutical composition.

In still another aspect, the present invention relates to a polynucleotide encoding the above eEF2 peptide (hereinafter, also referred to as eEF2 polynucleotide). The polynucleotide of the present invention may be a DNA or an RNA. The base sequence of the polynucleotide of the present invention can be determined on the basis of the amino acid sequence of the above eEF2 peptide. The above polynucleotide can be prepared, for example, by a DNA or RNA synthetic method, a PCR method and the like.

In another aspect, the present invention relates to an expression vector containing the above polynucleotide (hereinafter, also referred to as eEF2 expression vector). The types of expression vectors, sequences contained in addition to the above polynucleotide sequence and the like can be selected suitably depending on types of hosts into which the expression vector is introduced, the purpose of introducing the expression vector and the like. The expression vector of the present invention is administered to a subject to produce an eEF2 peptide in a living body and to induce an eEF2-specific CTL. The CTL impairs hematopoietic organ tumor cells, solid cancer cells and the like in a subject, thereby allowing the hematopoietic organ tumor and solid cancer to be treated or prevented.

In still another aspect, the present invention relates to a pharmaceutical composition for the treatment or prevention of cancer, comprising the above eEF2 polynucleotide or the above eEF2 expression vector. Composition, administration method and the like of the pharmaceutical composition of the present invention in this aspect are as described above.

In another aspect, the present invention relates to a method for the treatment or prevention of cancer, which comprises administering a pharmaceutical composition containing an effective amount of the above eEF2 polynucleotide or eEF2 expression vector to a subject. Cancers to be treated or prevented include, for example, lung adenocarcinoma, non-small cell lung cancer, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal squamous cell cancer, stomach cancer, colon cancer, pancreatic duct cancer, glioblastoma, malignant lymphoma and the like.

In still another aspect, the present invention relates to use of an eEF2 polynucleotide or an eEF2 expression vector for the production of a pharmaceutical composition containing the above eEF2 polynucleotide or eEF2 expression vector.

In another aspect, the present invention relates to cells containing the above eEF2 expression vector. The cells of the present invention can be prepared, for example, by transforming host cells such as E. coli, yeast, insect, and animal cells using the above expression vector. A method for introducing the expression vector into the host cells can be selected suitably from various methods. It is also possible to prepare the peptide of the present invention by culturing transformed cells, and recovering and purifying an eEF2 peptide produced.

In a further aspect, the present invention relates to an eEF2-specific CTL which is induced by the above eEF2 peptide. The CTL of the present invention recognizes a complex of an eEF2 peptide with an HLA-A*2402 molecule or an HLA-A*0201 molecule. Accordingly, HLA-A*2402-positive or HLA-A*0201-positive and highly eEF2-expressing tumor cells can be impaired specifically using the CTL of the present invention.

In another aspect, the present invention relates to a method for the treatment or prevention of cancer, which comprises administering an eEF2-specific CTL to an HLA-A*2402 positive or HLA-A*0201-positive subject. The administration method of the eEF2-specific CTL can be selected suitably depending on conditions such as types of diseases, a state of subjects, and targeted sites. The method may be, for example, intravenous administration, intradermal administration, subcutaneous administration, intramuscular administration, transnasal administration, or oral administration, but is not limited thereto.

In another aspect, the present invention relates to a method for inducing an eEF2-specific CTL, which comprises culturing peripheral blood mononuclear cells in the presence of the above HLA-A*2402-restricted eEF2 peptide or HLA-A*0201-restricted eEF2 peptide, and the eEF2-specific CTL is induced from the peripheral blood mononuclear cells. Subjects from which the peripheral blood mononuclear cells are derived may be any subjects so far as they have an HLA-A*2402 molecule or an HLA-A*0201 molecule. By culturing the peripheral blood mononuclear cells in the presence of the HLA-A*2402-restricted eEF2 peptide or HLA-A*0201-restricted eEF2 peptide, the eEF2-specific CTL is induced from CTL precursor cells in the peripheral blood mononuclear cells. By administering the eEF2-specific CTL obtained by the present invention to an HLA-A*2402-positive subject or an HLA-A*0201-positive subject, it is possible to treat or prevent a hematopoietic organ tumor and a solid cancer in the subject. In this connection, the peripheral blood mononuclear cells in the present specification include immature antigen-presenting cells (for example, precursors of dendritic cells, B-lymphocytes, macrophages, etc.) which are precursors of antigen-presenting cells. Since the immature antigen-presenting cells are contained, for example, in peripheral blood mononuclear cells and the like, such cells may be cultured in the presence of the above eEF2 peptide.

In still another aspect, the present invention relates to a kit for inducing an eEF2-specific CTL, comprising an HLA-A*2402-restricted eEF2 peptide or an HLA-A*0201-restricted eEF2 peptide as an essential constituent. Preferably, the kit is used in a method for inducing the above eEF2-specific CTL. The kit of the present invention may contain, for example, a sampling means of peripheral blood mononuclear cells, an adjuvant, a reaction vessel and the like, in addition to the above HLA-A*2402-restricted eEF2 peptide or HLA-A*0201-restricted eEF2 peptide. In general, the kit is accompanied with an instruction manual. The kit of the present invention can be used to induce efficiently the eEF2-specific CTL.

In a further aspect, the present invention relates to antigen-presenting cells (for example, dendritic cells, B-lymphocytes, macrophages, etc.) which present the above eEF2 peptide through an HLA-A*2402 molecule or an HLA-A*0201 molecule. The antigen-presenting cells of the present invention are induced by the above HLA-A*2402-restricted eEF2 peptide or HLA-A*0201-restricted eEF2 peptide. The above eEF2-specific CTL is efficiently induced using the antigen-presenting cells of the present invention.

In another aspect, the present invention relates to a method for the treatment or prevention of cancer, which comprises administering antigen-presenting cells, which present the above eEF2 peptide through an HLA-A*2402 molecule or an HLA-A*0201 molecule, to an HLA-A*2402-positive subject or an HLA-A*0201-positive subject. The administration method of the antigen-presenting cells can be selected suitably depending on conditions such as types of diseases, a state of subjects, and targeted sites. The method may be, for example, intravenous administration, intradermal administration, subcutaneous administration, intramuscular administration, transnasal administration, or oral administration, but is not limited thereto.

In a further aspect, the present invention relates to a method for preventing or treating cancer, which comprises inducing antigen-presenting cells which present an eEF2 peptide through an HLA-A*2402 molecule or an HLA-A*0201 molecule, the method comprising the steps of:

(a) reacting a sample with a nucleic acid having a nucleotide sequence encoding an amino acid sequence (SEQ ID NO:1) of an eEF2 protein or a partial sequence thereof, or the above eEF2 peptide,

(b) obtaining antigen-presenting cells which present the eEF2 peptide contained in the sample through the HLA-A*2402 molecule or HLA-A*0201 molecule, and

(c) administering the antigen-presenting cells to an HLA-A*2402-positive subject or an HLA-A*0201-positive subject. The sample in the above method may be any samples so far as they have a possibility of inclusion of lymphocytes or dendritic cells, and includes, for example, samples from a subject such as blood, cell culture media and the like. The reaction in the above method may be carried out using a conventional technique, preferably using an electroporation technique. The obtainment of the antigen-presenting cells can be carried out using a method known to those skilled in the art. The culture conditions of cells in a sample in each step can be determined suitably by those skilled in the art. The administration method of the antigen-presenting cells may be as described above.

Furthermore, the present invention relates to a kit for preventing or treating cancer, comprising, as an essential constituent, a nucleic acid having a nucleotide sequence encoding an amino acid sequence (SEQ ID NO:1) of an eEF2 protein or a partial sequence thereof, or an eEF2 peptide. The kit comprises antigen-presenting cells which present the above eEF2 peptide through an HLA-A*2402 molecule or an HLA-A*0201 molecule. Also, the kit of the present invention may contain, for example, a sampling means, a reaction vessel and the like, in addition to the above essential constituent. In general, the kit is accompanied with an instruction manual. The antigen-presenting cells which present an eEF2 peptide through an HLA-A*2402 molecule or an HLA-A*0201 molecule can be obtained efficiently using the kit of the present invention, and cancer can be treated or prevented by administering the antigen-presenting cells.

In another aspect, the present invention relates to an antibody against an HLA-A*2402-restricted eEF2 peptide or an HLA-A*0201-restricted eEF2 peptide, or an antibody against a polynucleotide encoding the peptide. The antibody of the present invention may be either a polyclonal antibody or a monoclonal antibody.

In a further aspect, the present invention relates to a method for diagnosing cancer, characterized by the use of the above eEF2-specific CTL, antigen-presenting cells which present the above eEF2 peptide through an HLA-A*2402 molecule or an HLA-A*0201 molecule, or an antibody against an HLA-A*2402-restricted eEF2 peptide or an HLA-A*0201-restricted eEF2 peptide or an antibody against a polynucleotide encoding the peptide. The eEF2-specific CTL is preferably used in the diagnosis method of the present invention. For example, cancer can be diagnosed by incubating the above CTL, antigen-presenting cells or antibody with a sample from an HLA-A*2402-positive subject or an HLA-A*0201-positive subject, or administering the above CTL, antigen-presenting cells or antibody to an HLA-A*2402-positive subject or an HLA-A*0201-positive subject, and then determining, for example, the position, site, amount or the like of the CTL, antigen-presenting cells or antibody. The above CTL, antigen-presenting cells or antibody may be labeled. By such labeling, the diagnosis method of the present invention can be carried out efficiently.

In another aspect, the present invention relates to a kit for diagnosis of cancer, comprising, as an essential constituent, the above eEF2-specific CTL, antigen-presenting cells which present an eEF2 peptide through an HLA-A*2402 molecule or an HLA-A*0201 molecule, or an antibody against an HLA-A*2402-restricted eEF2 peptide or an HLA-A*0201-restricted eEF2 peptide or an antibody against a polynucleotide encoding the peptide.

In a further aspect, the present invention relates to a method for determining the presence or amount of an eEF2-specific CTL in an HLA-A*2402-positive subject or an HLA-A*0201-positive subject, which comprises the steps of:

(a) reacting a complex of an eEF2 peptide and an HLA-A*2402 molecule or an HLA-A*0201 molecule with a sample from the subject, and then

(b) determining the presence or amount of the CTL recognizing the complex contained in the sample. The sample from the subject may be any samples so far as they have a possibility of inclusion of lymphocytes, and includes, for example, body fluid such as blood and lymph fluid, tissues and the like. The complex of an eEF2 peptide and an HLA-A*2402 molecule or an HLA-A*0201 molecule may be, for example, in the form of a tetramer, pentamer and the like, for example, using a method known to those skilled in the art such as a biotin-streptavidin method. The presence or amount of the CTL recognizing such a complex can be determined by a method known to those skilled in the art. In this aspect of the present invention, the above complex may be labeled. A known label such as a fluorescence label and a radioactive label can be used. By such labeling, the presence or amount of the CTL can be determined easily and rapidly. This aspect of the method of the present invention allows diagnosis of cancer, prognostic diagnosis and the like.

Thus, the present invention also provides a composition comprising a complex of an eEF2 peptide and an HLA-A*2402 molecule or an HLA-A*0201 molecule for determining the presence or amount of an eEF2-specific CTL in an HLA-A*2402-positive subject or an HLA-A*0201-positive subject.

Also, the present invention provides a kit for determining the presence or amount of an eEF2-specific CTL in an HLA-A*2402-positive subject or an HLA-A*0201-positive subject, comprising a complex of an eEF2 peptide and an HLA-A*2402 molecule or an HLA-A*0201 molecule.

In a further aspect, the present invention relates to a method for obtaining an eEF2-specific CTL using a complex of an eEF2 peptide and an HLA-A*2402 molecule or an HLA-A*0201 molecule, which comprises the steps of:

(a) reacting a sample with the complex, and

(b) obtaining the CTL which recognizes the complex contained in the sample.

The complex of an eEF2 peptide and an HLA-A*2402 molecule or an HLA-A*0201 molecule is as described above. The sample may be any samples so far as they have a possibility of inclusion of lymphocytes, and includes, for example, samples from a subject such as blood, cell culture media and the like. The obtainment of the CTL recognizing the complex can be carried out using a method known to those skilled in the art, for example, using FACS, MACS and the like. The eEF2-specific CTL obtained can be cultured to use for the treatment or prevention of a variety of cancers.

Thus, the present invention also relates to an eEF2-specific CTL, which can be obtained by a method for obtaining the eEF2-specific CTL using a complex of an eEF2 peptide and an HLA-A*2402 molecule or an HLA-A*0201 molecule.

Furthermore, the present invention relates to a kit for obtaining an eEF2-specific CTL, comprising a complex of an eEF2 peptide and an HLA-A*2402 molecule or an HLA-A*0201 molecule.

In one aspect, the present invention provides a kit for tumorigenesis characterized in that an eEF2 polypeptide is expressed. Thus, the kit of the present invention comprises, as an essential constituent, the step of expressing the eEF2 polypeptide in cells or non-human animals. Accordingly, a polynucleotide encoding an amino acid sequence of the polypeptide or a vector into which the polynucleotide is integrated is an essential constituent. In the present specification, the non-human animals refer to animals other than human. The kit of the present invention is based on a finding that forced expression of an eEF2 protein accelerates a G2/M phase in a cell cycle. The kit of the present invention may also contain, for example, a means for introducing the above polynucleotide or vector into cells or non-human animal tissues, a reagent for introduction, a reaction vessel and the like, in addition to the above polynucleotide or vector. In general, the kit is accompanied with an instruction manual. The kit of the present invention can be used for forming a tumor in vivo or in vitro, and then, for testing effects of candidate molecules against tumorigenesis or cell proliferation, for example.

In this regard, the method of the present invention may be carried out in vivo or in vitro.

EXAMPLES

The present invention is illustrated particularly and specifically by referring to the following examples, which should not be construed as limiting the present invention.

Example 1 Detection of EEF2 IgG Antibody in Sera of Cancer Patients

Cells of lung cancer cell lines PC14 and LU-99B, and leukemia cell line K562 were lysed in an SDS-sample buffer. Proteins contained in the buffer were separated by SDS-PAGE, and then transferred to a PVDF membrane. Solutions prepared by diluting sera obtained from 10 patients having lung cancer and 10 healthy subjects by 1500:1 were used as a primary antibody, and IgG antibodies bound to the membrane were visualized using an anti-human IgG antibody. As a result, a protein of about 100 kDa was found which was specifically recognized by the sera from the patients having lung cancer (FIG. 1). FIG. 1 is a typical example of a western blot. Subsequently, the protein was separated and identified as eEF2 by a mass spectrometric technique.

Excessive Expression of EEF2 in Various Cancers

Thin-sliced sections were prepared from paraffin-embedded blocks. After de-paraffin treatment, the sections were subjected to antigen-activating treatment in a citrate buffer (pH 6.0), reacted with an anti-eEF2 antibody (H-118, Santa Cruz Biotechnology, Santa Cruz, Calif., 1:100 dilution) at 4° C. overnight, and then reacted with Envision kit/HRP (Dako Cytomation) at room temperature for 30 minutes. After reacting with 0.7% of an H₂O₂ solution, the sections were color-developed using DAB as a substrate, and nuclear-staining was then carried out using hematoxylin. As a result, antibody-positive cells were observed in each affected tissue of patients having lung adenocarcinoma, small-cell lung cancer, head-and-neck squamous cell cancer, esophageal cancer, stomach cancer and colon cancer (FIGS. 2 to 4).

Detection of EEF2 Antibody in Various Types of Cancers

Peripheral blood was obtained from 72 patients having non-small cell lung cancer, 42 patients having colon cancer, 20 patients having head-and-neck squamous cell cancer, 18 patients having glioblastoma, and 17 healthy subjects in agreement. The blood was coagulated and sera were then obtained by centrifugation. A vector pGEX-5X-3 (GE) for expression of a recombinant protein was prepared by inserting a gene sequence encoding an amino acid sequence at positions 411-858 of eEF2. The recombinant GST-eEF2₄₁₁₋₈₅₈ protein purified was adjusted to 150 ng/lane and SDS-PAGE was carried out. The protein on the SDS-PAGE was electrically transferred to a PVDF membrane. The protein was reacted with sera diluted by 1500:1 at room temperature overnight, and IgG antibodies bound to the membrane were visualized using an anti-human IgG antibody. Density of the bands was measured and used as an anti-eEF2 antibody titer. Since the median value of the antibody titer in 17 healthy subjects was 500 densitometric units and the standard deviation was 500, the cutoff level was set to 2,000 densitometric units which was median+3 SD. As a result, it was found that, at a specificity of 94.7%, the eEF2 IgG antibody was positive in 66.7% of non-small cell lung cancer, 71.8% of colon cancer, 60.0% of head-and-neck squamous cell cancer, and 88.9% of glioblastoma (FIG. 5). Expression of the eEF2 protein in various cancers was analyzed by immunostaining. When the percentage of cancer cells showing intense stain as compared with corresponding normal cells was 25% or more of total cancer cells, the expression was judged to be positive (Table 8).

TABLE 8 Excessive expression of eEF2 in various cancers Positive rate of excessive Cancer expression of eEF2 Lung adenocarcinoma 100% (15/15) Small-cell lung cancer 95.0% (19/20) Esophageal cancer 58.3% (7/12) Stomack cancer 92.9% (13/14) Colon cancer 91.7% (22/24) Pancreatic duct cancer 55.6% (5/9) Malignant glioblastoma 50.6% (6/12) Malignant lymphoma 94.0% (47/50) Head-and-neck squamous cell 45.5% (5/11) cancer

Early Stage Detection of Cancer by EEF2 Antibody

The positive rate of eEF2 antibody titer was compared with the positive rate of CEA in 70 patients (44 in stage I, 13 in stage II, and 13 in stage III) having non-small cell lung cancer and having a clear serum CEA value. In this connection, the classification of stage I, stage II, and stage III was carried out according to the TNM classification defined by the International Union Against Cancer. The eEF2 antibody titer was determined by dot blotting. As a result, it was found that the positive rate of the eEF2 IgG antibody in each disease stage of non-small cell lung cancer was high even from stage I (Table 9).

TABLE 9 Stage I II III Anti-eEF2 Positive 81.8% 61.5% 61.5% IgG antibody rate CEA Positive 13.6% 23.1% 46.2% rate

Relationship Between EEF2 Antibody Titer and Disease-Free Survival Rate

Relationship between the eEF2 antibody titer in non-small cell lung cancer and disease-free survival rate was analyzed. Among 44 patients, the group (11 patients) having an eEF2 antibody titer of 4,000 or more densitometric units has a significantly high disease-free survival rate as compared with the group (26 patients) having an eEF2 antibody titer of 2,000 to 4,000 densitometric units and the group (7 patients) having an eEF2 antibody titer of less than 2,000 densitometric units (log rank test, FIG. 6).

Example 2 Inhibition of Cell Proliferation in Various Cell Lines

A vector expressing a siRNA which targets at sequence: 5′-caugggcaacaucaugaucgauccuguccu-3′ of an eEF2 mRNA (hereinafter, referred to as shEF2) was prepared using a tRNA-shRNA expression vector, piGENE tRNA Pur (Clontech, Palo Alto, Calif.). Subsequently, 10 μg of shEF2 or a vacant shRNA vector (shMock) was introduced by electroporation into stomach cancer cell lines AZ-521 and MKN28, colon cancer cell line SW620, lung cancer cell lines LU99B and PC-14, pancreatic cancer cell lines MiaPaCa2 and PCI6, glioblastoma cell lines A172 and U87MG, as well as malignant lymphoma cell lines IB4 and YT (each 5×10⁵ cells) expressing the eEF2 using Gene Pulser Xcell (trademark) system (Bio Rad, Hercules, Calif.) under a condition of 165 V and 1000 hF. After 24, 48, 72 and 96 hours of the introduction, cells were treated with trypsin and the number of surviving cells was counted. The experiments were carried out separately 3 times in duplicate. In all cases, the shEF2 significantly inhibited cell proliferation (FIGS. 7 and 8).

Example 3 Selection of EEF2 Peptide

Firstly, 4 peptides were selected by predicting sequences which can bind to an HLA-A*2402 molecule in an amino acid sequence of an eEF2 protein using ProPred-I website. The results are shown in Table 10 below.

(Table 10: Candidate eEF2 peptides having a high binding affinity to HLA-A*2402 molecule, selected using various programs (NetMHC3.0, Rankpep and SYFPEITHI))

TABLE 10 NetMHC3.0 Rankpep SYFPEITHI Starting Starting Starting residue Affinity Binding Log residue residue number (nM) level score number Score number Score 786 20 SB 0.721 633 18.484 786 25 633 188 WB 0.516 342 17.792 78 20 220 380 WB 0.451 477 15.220 265 19 342 416 WB 0.442 786 14.930 477 19 477 671 0.398 174 13.101 412 18 409 964 0.365 817 11.358 701 17 174 1130 0.350 684 11.215 409 16 684 1250 0.341 220 10.709 308 15 177 1611 0.317 409 10.641 311 15 265 1930 0.301 701 9.634 470 15 78 1958 0.299 714 9.556 512 15 412 2551 0.275 78 9.315 516 15 231 2665 0.271 412 8.827 594 15 729 2691 0.270 443 8.652 73 14 744 2829 0.265 364 8.246 252 14 73 3045 0.259 456 8.229 284 14 70 4080 0.232 213 8.072 328 14 644 4396 0.225 605 7.603 343 14 701 5322 0.207 265 7.401 434 14 759 6139 0.194 363 7.190 442 14 638 6593 491 7.188 456 14 602 6673 177 6.847 491 14 396 7134 442 6.419 509 14 284 7142 73 6.112 537 14 774 7954 850 6.015 657 14 736 8076 293 5.071 62 13 442 8141 166 4.961 70 13 290 8704 763 4.815 92 13 394 8917 670 4.451 95 13 300 8973 290 4.265 111 13 456 9299 285 4.229 180 13 227 9749 90 4.062 191 13 180 9862 335 4.016 201 13 578 9900 396 3.935 228 13 264 10704 453 3.878 258 13 491 11038 289 3.877 277 13 529 11225 1 3.85 293 13 293 12329 744 3.694 296 13 811 12728 649 3.487 299 13 299 12938 38 3.281 307 13

The starting residue number is the number shown in SEQ ID NO:1. All candidate eEF2 peptides are composed of 9 residues of amino acids. For example, a peptide having the starting residue number of 786 is a peptide composed of 9 amino acid residues from 786th residue A to 794th residue F in SEQ ID NO:1.

Next, a binding ability to an HLA-A2402 molecule was actually analyzed by an MHC stabilization assay. Briefly, T2-2402 cells (1×10⁶ cells), receiving forced expression of a human HLA-A*2402 molecule, not having an antigen-presenting ability to an HLA molecule, were incubated in an RPMI1640 medium containing 10 μM of a synthesized peptide and not containing a serum at 27° C. for 16 hours, and then allowed to stand at 37° C. for 3 hours. Since expression of an HLA-A24 molecule on a cell surface is stabilized by binding of a peptide, the expression of the HLA-A24 molecule on a cell surface after treatment with each peptide was analyzed by flow cytometry, and binding ability of each peptide to the HLA-A2402 molecule was evaluated. As a result, it was found that eEF2₄₀₉₋₄₁₇ (SEQ ID NO:4), eEF2₄₁₂₋₄₂₀ (SEQ ID NO:5), eEF2₇₀₁₋₇₀₉ (SEQ ID NO:6) and eEF2₇₈₆₋₇₉₄ (SEQ ID NO:7) peptides show a binding ability to the HLA-A2402 molecule (Table 11).

TABLE 11 Identification of HLA-A2402-restricted eEF2 peptide eEF2 Peptide Binding ability to HLA-A2402 molecule eEF2₄₀₉₋₄₁₇ + eEF2₄₁₂₋₄₂₀ + eEF2₇₀₁₋₇₀₉ + eEF2₇₈₆₋₇₉₄ +

Determination of Interferon Activity

T cells were incubated together with HLA-A*2402 molecule-expressing T2 cells pulsed with eEF2 peptides (eEF2₄₀₉₋₄₁₇, eEF2₄₁₂₋₄₂₀ and eEF2₇₀₁₋₇₀₉ peptides) in the presence of brefeldin A (Sigma) at 37° C. for 5 hours. After washing with PBS, CD3 and CD8 molecules which are cell surface antigens were stained by PerCP-conjugated anti-CD3 (BD Biosciences) and PE-conjugated anti-CD8 (Caltag, Burlingame, Calif.) antibodies on ice for 15 minutes. Subsequently, cells were fixed using Cytofix (BD Biosciences) on ice for 20 minutes, and intracellular IFN-γ was reacted with an FITC-conjugated anti-IFN-γ antibody (BD Biosciences) on ice for 30 minutes. Frequency of IFN-γ-positive cells present in CD8-positive T cells was analyzed using a flow cytometer. As a result, it was found that eEF2₄₀₉₋₄₁₇, eEF2₄₁₂₋₄₂₀ and eEF2₇₀₁₋₇₀₉ peptides increase the interferon-γ activity, and is therefore represent an HLA-A*2402-restricted peptide (FIG. 30).

Binding Affinity of Modified-Type EEF2 Peptides to HLA-A*2402 Molecule

Furthermore, a binding affinity of modified-type eEF2 peptides, in which an amino acid at position 2 (hereinafter, also referred to as P2) and/or at position 9 (hereinafter, also referred to as P9) in the amino acid sequences of eEF2₇₈₆₋₇₉₄ (SEQ ID NO:7) and eEF2₄₀₉₋₄₁₇ (SEQ ID NO:4) peptides among the above peptides was altered to another amino acid, was predicted as described above.

(Table 12: Prediction of binding affinity of modified-type eEF2₇₈₆₋₇₉₄ peptides (SEQ ID NOs:25 and 26) to HLA-A*2402 molecule)

TABLE 12 Amino Candidate acid Binding Log Peptide sequence Binding level score Score 786 AYLPVNESF 20 SB 0.721 14.930 786 I AYLPVNESI 43 SB 0.652 15.164 (SEQ ID NO: 25) 786 L AYLPVNESL 143 WB 0.541 14.547 (SEQ id no: 25) (Table 13: Prediction of binding affinity of modified-type eEF2₄₀₉₋₄₁₇ peptides (SEQ ID NOs:27 to 31) to HLA-A*2402 molecule)

TABLE 13 Can- Amino didate acid Binding Log Peptide sequence Binding level score Score 409 RFYAFGRVF 0.365 10.641 Y 409 RFYAFGRVF SB 0.641 15.653 (SEQ ID NO: 27) 409 I RFYAFGRVI 0.252 10.875 (SEQ ID NO: 28) Y 409 I RFYAFGRVI WB 0.556 15.887 (SEQ ID NO: 29) 409 L RFYAFGRVL 0.164 10.258 (SEQ ID NO: 30) Y 409 L RFYAFGRVL WB 0.434 15.270 (SEQ ID NO: 31)

Since the eEF2₇₈₆₋₇₉₄ (SEQ ID NO:7) peptide has Y at P2 and F at P9 and the Y and F are anchor residues, improvement of the binding affinity was not recognized even if the original residue is altered to another residue (Table 12). On the other hand, remarkable improvement of the binding affinity was recognized in the eEF2₄₀₉₋₄₁₇ (SEQ ID NO:4) peptide when the residue at P2 is altered to anchor residue Y (Table 13).

Induction of EEF2-Specific Killer T Cells

From peripheral blood mononuclear cells obtained from a donor having an HLA-A*2402 molecule, CD4⁺ CD25⁺ Treg cells were removed using CD25 MicroBeads (Miltenyi Biotech, Auburn, Calif.). Subsequently, monocytes of the donor were isolated using BD IMag CD14 isolation kit (BD Bioscience), and cultured in X-VIVO15 (Bio Whittaker, Walkersville, Md.) containing IL-4 and GM-CSF and supplemented with 1% human AB serum. Next day, IL-1β, IL-6, TNF-α and PGE-2 were added for maturation of dendritic cells, and culture was continued for further 3 days. The dendritic cells were irradiated (30 G), and then cultured in a medium containing 10 μg/mL of a peptide for 2 hours to pulse the dendritic cells with a peptide. The mononuclear cells (2×10⁶ cells) having Treg cells removed were then co-cultured with the dendritic cells pulsed with a peptide in a ratio of 10:1 to carry out stimulation by a peptide, and IL-2 was added to the medium on the next day. Subsequently, restimulation was carried out every 10 days by the donor mononuclear cells irradiated and pulsed with a peptide. After carrying out several times of stimulation, the cells were cultured in a medium containing IL-7 and IL-15, and T cell clones are established.

Determination of Cytotoxic Activity

From T cell clones established as described above, CD8-positive T cells were purified using CD8 Microbeads to prepare effector cells. Subsequently, target cells were incubated with ⁵¹Cr-labeled sodium chromate (Amersham Biosciences Corp., NJ) for 1 hour to label the cells. They were then mixed with the effector cells so that the ratio of cell count was 1:1, 3:1 and 9:1 of CTL/target cell (E/T) ratio, and the mixture was allowed to stand for 4 hours. The percentage of cells lysed was calculated according to the following equation:

Specific lysis %=[(cpm experimental release−cpm spontaneous release)/(cpm maximal release−cpm spontaneous release)]×100.

T2-2402 cells pulsed with an eEF2₇₈₆₋₇₉₄ pep tide were used as the target cells, and T2-2402 cells not pulsed with the eEF2₇₈₆₋₇₉₄ peptide (SEQ ID NO:7) as a negative control. As a result, it was shown that the specific lysis % of T2-2402 cells pulsed with the eEF2₇₈₆₋₇₉₄ peptide remarkably increases with the increase of the E/T ratio (FIG. 9). Also, colon cancer SW480 cells which show endogenous eEF2 expression and show HLA-A*2402 expression on a cell surface were used as the target cells, and stomach cancer AZ-521 cells and pancreatic cancer MiaPaCa2 cells which show endogenous eEF2 expression but do not show HLA-A*2402 expression on a cell surface as a negative control. As a result, it was shown that cytotoxic T cells activated by the eEF2₇₈₆₋₇₉₄ peptide specifically impair the cells which express the eEF2 and have the HLA-A*2402 molecule (FIG. 10).

Example 4 Selection of EEF2 Peptide

Peptides were selected by predicting sequences which can bind to an HLA-A*0201 molecule in an amino acid sequence of an eEF2 protein using ProPred-I website (Tables 1 to 7). Next, a binding ability to an HLA-A0201 molecule was actually analyzed by an MHC stabilization assay. Briefly, T2-0201 cells (1×10⁶ cells), receiving forced expression of a human HLA-A*0201 molecule, not having an antigen-presenting ability to an HLA molecule, were incubated in an RPMI1640 medium containing 10 aM of a synthesized peptide and not containing a serum at 27° C. for 16 hours, and then allowed to stand at 37° C. for 3 hours. Since expression of an HLA-A*0201 molecule on a cell surface is stabilized by binding of a peptide, the expression of the HLA-A0201 molecule on a cell surface after treatment with each peptide was analyzed by flow cytometry, and binding ability of each peptide to the HLA-A0201 molecule was evaluated. As a result, it was found that eEF2₂₈₄₋₂₉₂ (SEQ ID NO:13), eEF2₃₉₄₋₄₀₂ (SEQ ID NO:12), eEF2₅₁₉₋₅₂₇ (SEQ ID NO:9), eEF2₆₆₁₋₆₆₉ (SEQ ID NO:11). eEF2₆₇₁₋₆₇₉ (SEQ ID NO:10) and eEF2₇₃₉₋₇₄₇ (SEQ ID NO:8) peptides show a binding ability to the HLA-A*0201 molecule (Table 14).

TABLE 14 Binding ability of candidate peptide to HLA-A0201 class I molecule Amino acid % MFI Candidate peptide sequence MFI increase NS 5.8 Non-peptide 275.7 eEF2₂₉₂₋₃₀₀ LILDPIFKV 781.03 183.3 (SEQ ID NO: 14) eEF2₇₃₉₋₇₄₇ RLMEPIYLV 664.83 141.1 (SEQ ID NO: 8) eEF2₅₁₉₋₅₂₇ KLVEGLKRL 437.97 58.9 (SEQ ID NO: 9) eEF2₆₇₁₋₆₇₉ YLNEIKDSV 522.71 89.6 (SEQ ID NO: 10) eEF2₆₆₁₋₆₆₉ ILTDITKGV 828.16 200.4 (SEQ ID NO: 11) eEF2₃₉₄₋₄₀₂ LMMYISKMV 448.41 62.6 (SEQ ID NO: 12) eEF2₂₈₄₋₂₉₂ KLPRTFCQL 448.82 62.8 (SEQ ID NO: 13)

Determination of Interferon Activity

T cells were incubated together with HLA-A*0201 molecule-expressing T2 cells pulsed with HLA-A*0201-restricted eEF2 peptides in the presence of brefeldin A (Sigma) at 37° C. for 5 hours. After washing with PBS, CD3 and CD8 molecules which are cell surface antigens were stained by PerCP-conjugated anti-CD3 (BD Biosciences) and PE-conjugated anti-CD8 (Caltag, Burlingame, Calif.) antibodies on ice for 15 minutes. Subsequently, cells were fixed using Cytofix (BD Biosciences) on ice for 20 minutes, and intracellular IFN-γ was reacted with an FITC-conjugated anti-IFN-γ antibody (BD Biosciences) on ice for 30 minutes. Frequency of IFN-γ-positive cells present in CD8-positive T cells was analyzed using a flow cytometer. An eEF² ₇₃₉₋₇₄₇ peptide was used in FIG. 11, and an eEF2₆₆₁₋₆₆₉ peptide in FIG. 12. As a result, it was found that eEF2₆₆₁₋₆₆₉ (SEQ ID NO:11) and eEF2₇₃₉₋₇₄₇ (SEQ ID NO:8) peptides increase the interferon-γ activity (FIGS. 11 and 12).

Determination of Cytotoxic Activity

Next, evaluation was carried out as to whether the six candidate peptides [eEF2₇₃₉₋₇₄₇ (SEQ ID NO:8), eEF2₅₁₉₋₅₂₇ (SEQ ID NO:9), eEF2₆₇₁₋₆₇₉ (SEQ ID NO:10), eEF2₆₆₁₋₆₆₉ (SEQ ID NO:11), eEF2₃₉₄₋₄₀₂ (SEQ ID NO:12) and eEF2₂₈₄₋₂₉₂ (SEQ ID NO:13), excepting eEF2₂₉₂₋₃₀₀ (SEQ ID NO:14)] selected as described above actually have a cytotoxic activity. The experiments were carried out in much the same way as in the above Example 3. Thus, blood was taken from healthy donors having an HLA-A*0201 molecule, peripheral blood mononuclear cells were separated, and the first stimulation was carried out using the six candidate peptides (stimulator: self-PBMC). Subsequently, the peptide stimulation on the second day and later was carried out at intervals of 8 to 13 days (stimulator: allo B-LCL 3 mg/ml). Furthermore, IL-2 was added every 2 days after the second stimulation at a final concentration of 20 IU/ml. Cytotoxicity was measured on the 6th day after the final peptide stimulation. As a result, increase of cytotoxic activity was observed in the above 6 peptides (FIGS. 16 to 21). From the above fact, it was found that the above 6 peptides [eEF2₇₃₉₋₇₄₇ (SEQ ID NO:8), eEF2₅₁₉₋₅₂₇ (SEQ ID NO:9), eEF2₆₇₁₋₆₇₉ (SEQ ID NO:10), eEF2₆₆₁₋₆₆₉ (SEQ ID NO:11), eEF2₃₉₄₋₄₀₂ (SEQ ID NO:12) and eEF2₂₈₄₋₂₉₂ (SEQ ID NO:13)] bind to the HLA-A*0201 molecule and have a cytotoxic activity.

Next, evaluation was carried out as to whether the above 6 peptides and the eEF2₂₉₂₋₃₀₀ peptide (SEQ ID NO:14) can bind to an HLA-A*0206 molecule and produce interferon-γ. The experiments were carried out in the same way as in the above method, except that donors having the HLA-A*0206 molecule were used. As a result, it was found that all peptides tested increase the production of interferon-γ (FIG. 29).

Binding Affinity of Modified-Type EEF2 Peptides to HLA-A*0201 Molecule

Next, a binding affinity of modified-type eEF2 peptides, in which an amino acid at position 2 and/or position 9 in the above 6 peptides (eEF2₇₃₉₋₇₄₇, eEF2₅₁₉₋₅₂₇, eEF2₆₇₁₋₆₇₉, eEF2₆₆₁₋₆₆₉, eEF2₃₉₄₋₄₀₂ and eEF2₂₈₄₋₂₉₂) as well as eEF2₂₉₂₋₃₀₀ peptide (SEQ ID NO:14) was altered to another amino acid, was predicted using a program as described above (Tables 15 to 21).

TABLE 15 Prediction of binding affinity of modified-type (SEQ ID NOs: 32 to 34) of eEF2₇₃₉₋₇₄₇ peptide (SEQ ID NO: 8) to HLA-A*0201 molecule using two program (NetMHC3.0 and ProPred) NetMHC3.0 ProPred Amino acid Affinity Binding Log Real Log Peptide sequence (nM) level score score score eEF2₇₃₉₋₇₄₇ RLMEPIYLV 3 SB 0.880 2426.739 7.7943 eEF2₇₃₉₋₇₄₇ 2M RMMEPIYLV 3 SB 0.897 1752.645 7.4689 (SEQ ID NO: 32) eEF2₇₃₉₋₇₄₇ 9L RLMEPIYLL 4 SB 0.860 745.355 6.6139 (SEQ ID NO: 33) eEF2₇₃₉₋₇₄₇ 2M9L RMMEPIYLL 3 SB 0.877 538.312 6.2884 (SEQ ID NO: 34)

TABLE 16 Prediction of binding affinity of modified-type (SEQ ID NOs: 35 to 37) of eEF2₅₁₉₋₅₂₇ peptide (SEQ ID NO: 9) to HLA-A*0201 molecule using two program (NetMHC3.0 and ProPred) NetMHC3.0 ProPred Amino acid Affinity Binding Log Real Log Peptide sequence (nM) level score score score eEF2₅₁₉₋₅₂₇ KLVEGLKRL 289 WB 0.476 705.066 6.5583 eEF2₅₁₉₋₅₂₇2M KMVEGLKRL 201 WB 0.510 509.214 6.2329 (SEQ ID NO: 35) eEF2₅₁₉₋₅₂₇9V KLVEGLKRV 178 WB 0.521 2295.564 7.7387 (SEQ ID NO: 36) eEF2₅₁₉₋₅₂₇₂M9V KMVEGLKRV 112 WB 0.563 1657.907 7.4133 (SEQ ID NO: 37)

TABLE 17 Prediction of binding affinity of modified-type (SEQ ID NOs: 38 to 40) of eEF2₆₇₁₋₆₇₉ peptide (SEQ ID NO: 10) to HLA-A*0201 molecule using two program (NetMHC3.0 and ProPred) NetMHC3.0 ProPred Amino acid Affinity Binding Log Real Log Peptide sequence (nM) level score score score eEF2₆₇₁₋₆₇₉ YLNEIKDSV 11 SB 0.778 642.758 6.4658 eEF2₆₇₁₋₆₇₉2M YMNEIKDSV 10 SB 0.780 464.214 6.1403 (SEQ ID NO: 38) eEF2₆₇₁₋₆₇₉9L YLNEIKDSL 20 SB 0.723 197.418 5.2853 (SEQ ID NO: 39) eEF2₆₇₁₋₆₇₉2M9L YMNEIKDSL 21 SB 0.718 142.580 4.9599 (SEQ ID NO: 40)

TABLE 18 Prediction of binding affinity of modified-type (SEQ ID NOs: 41 to 43) of eEF2₆₆₁₋₆₆₉ peptide (SEQ ID NO: 11) to HLA-A*0201 molecule using two program (NetMHC3.0 and ProPred) NetMHC3.0 ProPred Amino acid Affinity Binding Log Real Log Peptide sequence (nM) level score score score eEF2₆₆₁₋₆₆₉ ILTDITKGV 46 SB 0.644 484.777 6.1837 eEF2₆₆₁₋₆₆₉2M IMTDITKGV 44 SB 0.649 350.117 5.8583 (SEQ ID NO: 41) eEF2₆₆₁₋₆₆₉9L ILTDITKGL 82 WB 0.592 148.896 5.0032 (SEQ ID NO: 42) eEF2₆₆₁₋₆₆₉2M9L IMTDITKGL 88 WB 0.585 107.536 4.6778 (SEQ ID NO: 43)

TABLE 19 Prediction of binding affinity of modified-type (SEQ ID NOs: 44 to 46) of eEF2₃₉₄₋₄₀₂ peptide (SEQ ID NO: 12) to HLA-A*0201 molecule using two program (NetMHC3.0 and ProPred) NetMHC3.0 ProPred Amino acid Affinity Binding Log Real Log Peptide sequence (nM) level score score score eEF2₃₉₄₋₄₀₂ LMMYISKMV 24 SB 0.704 315.959 5.7556 eEF2₃₉₄₋₄₀₂2L LLMYISKMV 44 SB 0.648 437.482 6.0810 (SEQ ID NO: 44) eEF2₃₉₄₋₄₀₂9V LMMYISKML 83 WB 0.591 97.045 4.5752 (SEQ ID NO: 45) eEF2₃₉₄₋₄₀₂2L9L LLMYISKML 139 WB 0.544 134.369 4.9006 (SEQ ID NO: 46)

TABLE 20 Prediction of binding affinity of modified-type (SEQ ID NOs: 47 to 49) of eEF2₂₈₄₋₂₉₂ peptide (SEQ ID NO: 13) to HLA-A*0201 molecule using two program (NetMHC3.0 and ProPred) NetMHC3.0 ProPred Amino acid Affinity Binding Log Real Log Peptide sequence (nM) level score score score eEF2₂₈₄₋₂₉₂ KLPRTFCQL 1145 0.705 142.060 4.9562 eEF2₂₈₄₋₂₉₂2M KMPRTFCQL 983 0.363 102.599 4.6308 (SEQ ID NO: 47) eEF2₂₈₄₋₂₉₂9V KLPRTFCQV 331 WB 0.463 462.521 6.1367 (SEQ ID NO: 48) eEF2₂₈₄₋₂₉₂2M9L KMPRTFCQV 228 WB 0.498 334.043 5.8113 (SEQ ID NO: 49)

TABLE 21 Prediction of binding affinity of modified-type (SEQ ID NOs: 15 to 17 and 24) of eEF2₂₉₂₋₃₀₀ peptide (SEQ ID NO: 14) to HLA-A*0201 molecule using two program (NetMHC3.0 and ProPred) ProPred NetMHC3.0 Amino acid Real Log Affinity Binding Log Peptide sequence score score (nM) level score eEF2₂₉₂₋₃₀₀ LILDPIFKV 3290.05 8.10 8 SB 0.802 eEF2₂₉₂₋₃₀₀2L LLLDPIFKV 23927.65 10.08 3 SB 0.898 (SEQ ID NO: 15) eEF2₂₉₂₋₃₀₀2M LMLDPIFKV 17281.08 9.76 3 SB 0.898 (SEQ ID NO: 16) eEF2₂₉₂₋₃₀₀2L9L LLLDPIFKL 7349.21 8.90 3 SB 0.872 (SEQ ID NO: 17) eEF2₂₉₂₋₃₀₀2M9L LMLDPIFKL 5307.76 8.58 3 SB 0.872 (SEQ ID NO: 18)

In addition, on modified-type peptides (SEQ ID NOs:15 to 17 and 24) of eEF2₂₉₂₋₃₀₀ (SEQ ID NO:14) among the above peptides, a binding affinity to the HLA-A*0201 molecule (Table 22), cytotoxicity (FIGS. 22 to 25) and an interferon-γ activity (FIG. 26) were actually evaluated using a method as described above.

TABLE 22 Binding assay (stabilization assay) of modified-type eEF2₂₉₂₋₃₀₀ peptides Amino acid Peptide sequence MIF % MIF increase Ns 4.96 Non-peptide 84.50 eEF2₂₉₂₋₃₀₀ LILDPIFKV 311.69 268.86 eEF2₂₉₂₋₃₀₀ 2L LLLDPIFKV 338.80 300.95 eEF2₂₉₂₋₃₀₀ 2M LMLDPIFKV 313.14 270.58 eEF2₂₉₂₋₃₀₀ 2L9L LLLDPIFKL 319.26 277.82 eEF2₂₉₂₋₃₀₀ 2M9L LMLDPIFKL 275.42 225.94

As a result, it was found that, among the modified-type eEF2₂₉₂₋₃₀₀ peptides, eEF2₂₉₂₋₃₀₀ 2L (a peptide having alteration of from I to L in an amino acid at position 2 in the eEF2₂₉₂₋₃₀₀ peptide, SEQ ID NO:15), eEF2₂₉₂₋₃₀₀ 2M (a peptide having alteration of from I to M in an amino acid at position 2 in the eEF2₂₉₂₋₃₀₀ peptide, SEQ ID NO:16), eEF2₂₉₂₋₃₀₀ 2L9L (a peptide having alteration of from I to L in an amino acid at position 2 and of from V to L in an amino acid at position 9 in the eEF2₂₉₂₋₃₀₀ peptide, SEQ ID NO:17) and eEF2₂₉₂₋₃₀₀ 2M9L (a peptide having alteration of from I to M in an amino acid at position 2 and of from V to L in an amino acid at position 9 in the eEF2₂₉₂₋₃₀₀ peptide, SEQ ID NO:24) have a binding affinity to the HLA-A*0201 molecule higher than that of the original eEF2₂₉₂₋₃₀₀ peptide (Table 22), and increase cytotoxicity and interferon-γ activity in human (FIGS. 22 to 26, and 28).

Example 5 Forced Expression of EEF2 in Cancer Cell Line

Cell clones were established in which an eEF2 expression vector or a vacant expression vector was expressed in stomach cancer cell line AZ-521. The eEF2 expression vector is one in which a nucleotide sequence of an eEF2 gene is inserted into a restriction enzyme cleavage site: EcoRI of pcDNA3.1 (+) (Invitrogen). These cells were cultured without synchronization, and doubling time of the cells was calculated from cell counts after 48 and 72 hours from the beginning of culture. Furthermore, 1×10⁵ cells were fixed with 80% ethanol and then allowed to stand in PBS containing propidium iodide (PI, 5 μg/ml) and RNaseA (200 μg/ml) for 30 minutes, and distribution of each phase of cell cycle was analyzed by flow cytometry (FIG. 13, left upper graph). Since the doubling time of cells corresponds to length of the cell cycle, the time was then multiplied by proportional distribution of each phase of cell cycle to calculate progression time of each phase (FIG. 13, right upper graph and lower table). As a result, it was observed that the cell count in a G2/M phase decreases and the progression time is shortened in cells having eEF2 expressed (FIG. 13). This suggests that the eEF2 accelerates progression of the G2/M phase.

Each of 5×10⁶ cells of stomach cancer cell line AZ-521 having eEF2 forcibly expressed (2 clones) and AZ-521 having a control vacant vector expressed (2 clones) established as described above was mixed with Matrigel (Becton Dickinson), and the mixture was subcutaneously injected into left and right abdominal regions of nude mice to form a tumor. The size of the tumor was measured twice a week, and observed for 34 days. Volume (mm³) of the tumor was calculated by (minor axis)²×(major axis)²/2. The results of three experiments carried out separately on each clone are shown (FIG. 14). From the results, it was shown that the volume of the tumor remarkably increases in mice injected with cells having eEF2 forcibly expressed as compared with a control. FIG. 15 shows a typical example. The left tumor is caused by AZ-521 cells having a vacant vector expressed, and the right tumor by AZ-521 cells having eEF2 forcibly expressed.

Example 6 Identification of Novel Target Sequence of ShRNA Targeting at EEF2

In order to develop an shRNA (hereinafter, referred to as shEF2) which can efficiently inhibit expression of eEF2 by targeting at the eEF2 and inhibit growth of cancer, two sequences (hereinafter, referred to as shEF-1918 and shEF-2804) were newly selected which can be targets in an eEF2 sequence.

A target sequence at positions 1918-1947 (positions 1918-1947 from the 5′ end of a DNA sequence encoding an eEF2 protein) in an eEF2 gene: 5′-gcc tggccgagga catcgataaa ggcgagg-3′ (SEQ ID NO:18).

A target sequence at positions 2804-2833 (positions 2804-2833 from the 5′ end of a DNA sequence encoding an eEF2 protein) in an eEF2 gene: 5′-actcaac cataacactt gatgccgttt ctt-3′ (SEQ ID NO:19).

Construction of ShRNA

In order to construct an shRNA for the above sequences (SEQ ID NOs:18 and 19), a DNA sequence [shEF-1918 or shEF-2804 (sense strand)] consisting of a sense sequence of a target sequence (30 bases)—a loop sequence (10 bases)—an antisense sequence (30 bases), and its complementary DNA sequence [shEF-1918 or shEF-2804 (antisense strand)] were chemically synthesized and then annealed, and the product was inserted into SacI and KpnI recognition sites of tRNA-shRNA expression vector, piGENE tRNA Pur (Clontech, Palo Alto, Calif.). Such DNA sequences inserted are shown below. In this connection, variations were added to a portion of a sense sequence of a target sequence so that an antisense strand is efficiently taken into RISC when an RNA having a sequence transcribed is cleaved (shown by underlines in the following sequences).

shEF-1918 (sense strand): (SEQ ID NO: 20) 5′-(gcc tggccgagga catcgatgaa agcgtgg) cttcctgtca (cctcgcc tttatcgatg tcctcggcca ggc)-3′ shEF-1918 (antisense strand): (SEQ ID NO: 21) 3′-(cgg accggctcct gtagctactt tcgcacc) gaaggacagt (ggagcgg aaatagctac aggagccggt ccg)-5′ shEF-2804 (sense strand): (SEQ ID NO: 22) 5′-(actcaac cataacactt gataccattt gtt) cttcctgtca (aag aaacggcatc aagtgttatg gttgagt)-3′ shEF-2804 (antisense strand): (SEQ ID NO: 23) 3′-(tgagttg gtattgtgaa ctatggtaaa caa) gaaggacagt (ttc tttgccgtag ttcacaatac caactca)-5′

Cell Culture and Introduction of ShRNA

Lung cancer cell PC-14, pancreatic cancer cell PCI6, fibrosarcome cell HT-1080 and malignant glioma cell A172 were cultured in DMEM containing 10% FBS. In order to introduce an shRNA, cells (1×10⁵) were washed twice with PBS and then suspended in 250 μL of an FBS-free RPMI1640 medium, each 10 ug of shEF-1918, shEF-2804, or a shRNA vector for Luciferase, shLuc dissolved in 50 uL of an FBS-free RPMI1640 medium was added to the suspension, and electroporation was carried out using Gene Pulsor II (BioRad) under a condition of 950 μFD and 175 V. Survival rate of cells was about 90% under this condition. After the introduction of the shRNA, the number of living cells was counted, the cells were seeded at a density of 1×10⁵ cells/mL, trypsin treatment was carried out after 72 hours, and the number of cells was counted. As a result, shEF-1918 and shEF-2804 significantly inhibited cell proliferation in all four types of cells analyzed as compared with shLuc (FIG. 27).

INDUSTRIAL APPLICABILITY

The present invention provides a method for detecting cancer using eEF2 as a marker, a pharmaceutical composition for treatment or prevention targeting at eEF2, an HLA-A*2402-restricted or HLA-A*0201-restricted eEF2 peptide, a pharmaceutical composition containing them, and others, and is therefore applicable in the field of pharmaceuticals, for example, in the field of development and production of preventive or therapeutic pharmaceuticals for various hematopoietic organ tumors or solid cancers highly expressing an eEF2 gene.

Sequence Listing Free Text

SEQ ID NO:2: eEF2 siRNA SEQ ID NO:3: eEF2 siRNA SEQ ID NO:18: eEF2 1918-1947 SEQ ID NO:19: eEF2 2804-2833 SEQ ID NO:20: shEF-1918 sense SEQ ID NO:21: shEF-1918 antisense SEQ ID NO:22: shEF-2804 sense SEQ ID NO:23: shEF-2804 antisense 

1. A method for the treatment or prevention of cancer in an HLA-A*0201-positive subject, comprising administering to the subject an eEF2 peptide having an amino acid sequence composed of contiguous amino acids derived from an eEF2 protein, wherein the amino acid sequence is selected from the group consisting of: (a) (SEQ ID NO: 8) Arg Leu Met Glu Pro Ile Tyr Leu Val; (b) (SEQ ID NO: 9) Lys Leu Val Glu Gly Leu Lys Arg Leu; (c) (SEQ ID NO: 10) Tyr Leu Asn Glu Ile Lys Asp Ser Val; (d) (SEQ ID NO: 11) Ile Leu Thr Asp Ile Thr Lys Gly Val; (e) (SEQ ID NO: 12) Leu Met Met Tyr Ile Ser Lys Met Val; (f) (SEQ ID NO: 13) Lys Leu Pro Arg Thr Phe Cys Gln Leu; (g) (SEQ ID NO: 14) Leu Ile Leu Asp Pro Ile Phe Lys Val;

and (h) an amino acid sequence having substitution, deletion or addition of one or several amino acids in the amino acid sequences as shown in (a) to (g).
 2. The method according to claim 1, wherein the amino acid sequence is Arg Leu Met Glu Pro Ile Tyr Leu Val (SEQ ID NO:8) or Ile Leu Thr Asp Ile Thr Lys Gly Val (SEQ ID NO:11).
 3. The method according to claim 1, wherein the amino acid sequence has, in the Leu Ile Leu Asp Pro Ile Phe Lys Val (SEQ ID NO:14), a substitution of the amino acid Ile at position 2 with Leu or Met, and/or a substitution of the amino acid Val at position 9 with Leu.
 4. The method according to any one of claims 1 to 3, wherein the cancer is selected from the group consisting of lung adenocarcinoma, small-cell lung cancer, esophageal cancer, stomach cancer, colon cancer, pancreatic duct cancer, malignant glioblastoma, malignant lymphoma and head-and-neck squamous cell cancer. 